v4.3.0

changelog.md

@@ -1,5 +1,82 @@
 # Changelog
 
+## 2026-02-03 - 4.3.0 - feat(docs)
+add LocalTsmDb documentation and examples; update README code samples and imports; correct examples and variable names; update package author
+
+- Introduce LocalTsmDb: zero-config local database with automatic persistence, auto port discovery, and pre-connected client (added Quick Start, API, Features, and testing examples).
+- Expand comparison table to include LocalTsmDb alongside SmartMongo and TsmDB.
+- Update README examples: new LocalTsmDb usage, reorder options (LocalTsmDb, TsmDB, SmartMongo), rename test DB variable (db -> testDb), and adjust test snippets for Jest/Mocha and tap. 
+- Adjust code snippets and API notes: switch some example imports to use tsmdb, replace FileStorageAdapter references, change planner.createPlan to await planner.plan, and use wal.getEntriesAfter(...) without awaiting. 
+- Update package.json author from 'Lossless GmbH' to 'Task Venture Capital GmbH'.
+
+## 2026-02-03 - 4.2.1 - fix(package.json)
+replace main and typings with exports field pointing to ./dist_ts/index.js
+
+- Added package.json exports field mapping "." to ./dist_ts/index.js to declare the package entrypoint.
+- Removed main (dist_ts/index.js) and typings (dist_ts/index.d.ts) entries.
+- Note: switching to exports improves Node resolution but removing the typings entry may affect TypeScript consumers expecting index.d.ts.
+
+## 2026-02-01 - 4.2.0 - feat(tsmdb)
+implement TsmDB Mongo-wire-compatible server, add storage/engine modules and reorganize exports
+
+- Add full TsmDB implementation under ts/ts_tsmdb: wire protocol, server, command router, handlers, engines (Query, Update, Aggregation, Index, Transaction, Session), storage adapters (Memory, File), OpLog, WAL, utils and types.
+- Remove legacy ts/tsmdb implementation and replace with new ts_tsmdb module exports.
+- Introduce ts/ts_mongotools module and move SmartMongo class there; update top-level exports in ts/index.ts to export SmartMongo, tsmdb (from ts_tsmdb) and LocalTsmDb.
+- Add LocalTsmDb convenience class (ts/ts_local) to start a file-backed TsmDB and return a connected MongoClient.
+- Refactor plugin imports into per-module plugins files and add utilities (checksum, persistence, query planner, index engine).
+
+## 2026-02-01 - 4.1.1 - fix(tsmdb)
+add comprehensive unit tests for tsmdb components: checksum, query planner, index engine, session, and WAL
+
+- Add new tests: test.tsmdb.checksum.ts — CRC32 and document checksum utilities (add/verify/remove)
+- Add new tests: test.tsmdb.queryplanner.ts — QueryPlanner plans, index usage, selectivity, explain output, and edge cases
+- Add new tests: test.tsmdb.indexengine.ts — Index creation, unique/sparse options, candidate selection, and constraints
+- Add new tests: test.tsmdb.session.ts — Session lifecycle, touch/refresh/close, extractSessionId handling
+- Add new tests: test.tsmdb.wal.ts — WAL initialization, LSN increments, logging/recovery for inserts/updates/deletes, binary and nested data handling
+- Tests only — no production API changes; increases test coverage
+- Recommend patch bump from 4.1.0 to 4.1.1
+
+## 2026-02-01 - 4.1.0 - feat(readme)
+expand README with storage integrity, WAL, query planner, session & transaction docs; update test script to enable verbose logging and increase timeout
+
+- Updated npm test script to run tstest with --verbose, --logfile and --timeout 60 to improve test output and avoid timeouts.
+- Extensive README additions: file storage adapter examples with checksum options, write-ahead logging (WAL) usage and recovery, query planner examples, index and query execution details, session and transaction examples and features.
+- Wire protocol / features table updated to include Transactions and Sessions and added admin commands (dbStats, collStats).
+- Architecture diagram and component list updated to include QueryPlanner, SessionEngine, TransactionEngine and WAL; storage layer annotated with checksums and WAL.
+- Minor example import tweak: MongoClient import now includes Db type in test examples.
+
+## 2026-02-01 - 4.0.0 - BREAKING CHANGE(storage,engine,server)
+add session & transaction management, index/query planner, WAL and checksum support; integrate index-accelerated queries and update storage API (findByIds) to enable index optimizations
+
+- Add SessionEngine with session lifecycle, auto-abort of transactions on expiry and session tracking in CommandRouter and AdminHandler.
+- Introduce TransactionEngine integrations in CommandRouter and AdminHandler; handlers now support start/commit/abort transaction workflows.
+- Add IndexEngine enhancements including a simple B-tree and hash map optimizations; integrate index usage into Find/Count/Insert/Update/Delete handlers for index-accelerated queries and index maintenance on mutations.
+- Add QueryPlanner to choose IXSCAN vs COLLSCAN and provide explain plans.
+- Add WAL (write-ahead log) for durability, with LSNs, checkpoints and recovery APIs.
+- Add checksum utilities and FileStorageAdapter support for checksums (enableChecksums/strictChecksums), with verification on read and optional strict failure behavior.
+- IStorageAdapter interface changed to include findByIds; MemoryStorageAdapter and FileStorageAdapter implement findByIds to support index lookups.
+- Exported API additions: WAL, QueryPlanner, SessionEngine, checksum utilities; CommandRouter now caches IndexEngines and exposes transaction/session engines.
+- Breaking change: the IStorageAdapter interface change requires third-party storage adapters to implement the new findByIds method.
+
+## 2026-02-01 - 3.0.0 - BREAKING CHANGE(tsmdb)
+rename CongoDB to TsmDB and relocate/rename wire-protocol server implementation and public exports
+
+- Project refactor renames the in-memory wire-protocol server from CongoDB -> TsmDB (identifiers, files and namespaces changed).
+- ts/index.ts now exports tsmdb instead of congodb (public API change; consumers must update imports).
+- All congodb sources under ts/congodb were removed and equivalent implementations added under ts/tsmdb (errors, engines, storage adapters, server, handlers, WireProtocol, types).
+- Readme and usage examples updated to reference TsmDB/tsmdb and example code updated accordingly.
+- Tests renamed/updated from test.congodb.ts -> test.tsmdb.ts to exercise the new tsmdb export and server.
+
+## 2026-01-31 - 2.2.0 - feat(readme)
+update README with expanded documentation covering CongoDB and SmartMongo, installation, quick start examples, architecture, usage examples, and legal/company information
+
+- Completely expanded README: added detailed overview for SmartMongo and new CongoDB (wire-protocol server)
+- Added Quick Start examples for both SmartMongo and CongoDB (TypeScript/ESM snippets)
+- Included installation instructions for npm and pnpm and issue reporting/security guidance
+- Added architecture diagram, example tests, and storage/engine descriptions
+- Clarified license, trademark, and company contact information
+- Large non-functional documentation-only change (+398 -44)
+
 ## 2026-01-31 - 2.1.0 - feat(congodb)
 implement CongoDB MongoDB wire-protocol compatible in-memory server and APIs
 

package.json

@@ -1,15 +1,16 @@
 {
   "name": "@push.rocks/smartmongo",
-  "version": "2.1.0",
+  "version": "4.3.0",
   "private": false,
   "description": "A module for creating and managing a local MongoDB instance for testing purposes.",
-  "main": "dist_ts/index.js",
-  "typings": "dist_ts/index.d.ts",
+  "exports": {
+    ".": "./dist_ts/index.js"
+  },
   "type": "module",
-  "author": "Lossless GmbH",
+  "author": "Task Venture Capital GmbH",
   "license": "MIT",
   "scripts": {
-    "test": "(tstest test/)",
+    "test": "(tstest test/. --verbose --logfile --timeout 60)",
     "build": "(tsbuild --web)",
     "buildDocs": "tsdoc"
   },

readme.hints.md

@@ -9,21 +9,21 @@
 - **Why:** Deno wraps CommonJS exports in a `default` property, so default imports are required
 - Fixed in version 2.0.13 (changed from `import * as mongoPlugin`)
 
-## CongoDB - MongoDB Wire Protocol Server
+## TsmDB - MongoDB Wire Protocol Server
 
 ### Architecture
-CongoDB implements the MongoDB binary wire protocol (OP_MSG, OP_QUERY) allowing official MongoDB drivers to connect directly.
+TsmDB implements the MongoDB binary wire protocol (OP_MSG, OP_QUERY) allowing official MongoDB drivers to connect directly.
 
 ```
-Official MongoClient  →  TCP (wire protocol)  →  CongoServer  →  Engines  →  Storage
+Official MongoClient  →  TCP (wire protocol)  →  TsmdbServer  →  Engines  →  Storage
      (mongodb npm)           OP_MSG/BSON            (port)
 ```
 
 ### Module Structure
 ```
-ts/congodb/
+ts/tsmdb/
 ├── server/                   # Wire protocol server
-│   ├── CongoServer.ts        # TCP server, connection handling
+│   ├── TsmdbServer.ts        # TCP server, connection handling
 │   ├── WireProtocol.ts       # OP_MSG/OP_QUERY parsing & encoding
 │   ├── CommandRouter.ts      # Route commands to handlers
 │   └── handlers/             # Command implementations
@@ -53,11 +53,11 @@ ts/congodb/
 
 ### Usage Example
 ```typescript
-import { CongoServer } from '@push.rocks/smartmongo/congodb';
+import { TsmdbServer } from '@push.rocks/smartmongo/tsmdb';
 import { MongoClient } from 'mongodb';
 
 // Start server
-const server = new CongoServer({ port: 27117 });
+const server = new TsmdbServer({ port: 27117 });
 await server.start();
 
 // Connect with official MongoDB driver
@@ -82,8 +82,3 @@ await server.stop();
 - **Aggregation**: aggregate, count, distinct
 - **Indexes**: createIndexes, dropIndexes, listIndexes
 - **Admin**: ping, listDatabases, listCollections, drop, dropDatabase, create, serverStatus, buildInfo
-
-### Notes
-- The old CongoClient/CongoDb/CongoCollection classes have been removed
-- Use the official `mongodb` npm package's MongoClient instead
-- Server supports MongoDB wire protocol versions 0-21 (MongoDB 3.6 through 7.0 compatible)

readme.md

@@ -1,104 +1,677 @@
 # @push.rocks/smartmongo
 
-create a local mongodb for testing
+A powerful MongoDB toolkit for testing and development — featuring a real MongoDB memory server (**SmartMongo**), an ultra-fast wire-protocol-compatible in-memory database server (**TsmDB**), and a zero-config local database (**LocalTsmDb**). 🚀
 
 ## Install
 
-To start using @push.rocks/smartmongo in your project, you first need to install it via npm. You can do this by running the following command in your terminal:
-
 ```bash
 npm install @push.rocks/smartmongo --save-dev
+# or
+pnpm add -D @push.rocks/smartmongo
 ```
 
-This will add `@push.rocks/smartmongo` as a development dependency to your project because it's typically used for testing purposes.
+## Issue Reporting and Security
 
-## Usage
+For reporting bugs, issues, or security vulnerabilities, please visit [community.foss.global/](https://community.foss.global/). This is the central community hub for all issue reporting. Developers who sign and comply with our contribution agreement and go through identification can also get a [code.foss.global/](https://code.foss.global/) account to submit Pull Requests directly.
 
-The `@push.rocks/smartmongo` package provides a convenient way to spin up a local MongoDB instance, primarily for testing purposes. It's designed to simplify the process of configuring and managing a MongoDB replica set during development or in CI/CD pipelines. Below, we present a comprehensive guide on how to utilize the full feature set of this module, employing ESM syntax and TypeScript.
+## Overview
 
-### Setting Up
+`@push.rocks/smartmongo` provides three powerful approaches for MongoDB in testing and development:
 
-To get started, you must first import the `SmartMongo` class from the package. This class is responsible for handling the MongoDB instances.
+| Feature | SmartMongo | TsmDB | LocalTsmDb |
+|---------|------------|-------|------------|
+| **Type** | Real MongoDB (memory server) | Wire protocol server | Zero-config local DB |
+| **Speed** | ~2-5s startup | ⚡ Instant (~5ms) | ⚡ Instant + auto-connect |
+| **Compatibility** | 100% MongoDB | MongoDB driver compatible | MongoDB driver compatible |
+| **Dependencies** | Downloads MongoDB binary | Zero external deps | Zero external deps |
+| **Replication** | ✅ Full replica set | Single node | Single node |
+| **Persistence** | Dump to directory | Memory or file | File-based (automatic) |
+| **Use Case** | Integration testing | Unit testing, CI/CD | Quick prototyping, local dev |
+
+## 🚀 Quick Start
+
+### Option 1: LocalTsmDb (Zero-Config Local Database) ⭐ NEW
+
+The easiest way to get started — just point it at a folder and you have a persistent MongoDB-compatible database with automatic port discovery!
+
+```typescript
+import { LocalTsmDb } from '@push.rocks/smartmongo';
+
+// Create a local database backed by files
+const db = new LocalTsmDb({ folderPath: './my-data' });
+
+// Start and get a connected MongoDB client
+const client = await db.start();
+
+// Use exactly like MongoDB
+const users = client.db('myapp').collection('users');
+await users.insertOne({ name: 'Alice', email: 'alice@example.com' });
+
+const user = await users.findOne({ name: 'Alice' });
+console.log(user); // { _id: ObjectId(...), name: 'Alice', email: 'alice@example.com' }
+
+// Data persists to disk automatically!
+await db.stop();
+
+// Later... data is still there
+const db2 = new LocalTsmDb({ folderPath: './my-data' });
+const client2 = await db2.start();
+const savedUser = await client2.db('myapp').collection('users').findOne({ name: 'Alice' });
+// savedUser exists!
+```
+
+### Option 2: TsmDB (Wire Protocol Server)
+
+A lightweight, pure TypeScript MongoDB-compatible server — use the official `mongodb` driver directly!
+
+```typescript
+import { tsmdb } from '@push.rocks/smartmongo';
+import { MongoClient } from 'mongodb';
+
+// Start TsmDB server
+const server = new tsmdb.TsmdbServer({ port: 27017 });
+await server.start();
+
+// Connect with the official MongoDB driver
+const client = new MongoClient('mongodb://127.0.0.1:27017');
+await client.connect();
+
+// Use exactly like real MongoDB
+const db = client.db('myapp');
+await db.collection('users').insertOne({ name: 'Alice', age: 30 });
+
+const user = await db.collection('users').findOne({ name: 'Alice' });
+console.log(user); // { _id: ObjectId(...), name: 'Alice', age: 30 }
+
+// Clean up
+await client.close();
+await server.stop();
+```
+
+### Option 3: SmartMongo (Real MongoDB)
+
+Spin up a real MongoDB replica set in memory — perfect for integration tests that need full MongoDB compatibility.
 
 ```typescript
 import { SmartMongo } from '@push.rocks/smartmongo';
+
+// Start a MongoDB replica set
+const mongo = await SmartMongo.createAndStart();
+
+// Get connection details
+const descriptor = await mongo.getMongoDescriptor();
+console.log(descriptor.mongoDbUrl); // mongodb://127.0.0.1:xxxxx/...
+
+// Use with your MongoDB client or ORM
+// ... run your tests ...
+
+// Clean up
+await mongo.stop();
 ```
 
-### Creating and Starting a MongoDB Instance
+## 📖 LocalTsmDb API
 
-With `SmartMongo`, you can easily create and start a MongoDB replica set. You can specify the number of replica instances; however, if not specified, it defaults to 1.
+The simplest option for local development and prototyping — zero config, auto port discovery, and automatic persistence.
+
+### Basic Usage
 
 ```typescript
-async function setupMongoDB() {
-  const smartMongoInstance = await SmartMongo.createAndStart(1); // Number of replicas is optional
-  return smartMongoInstance;
-}
+import { LocalTsmDb } from '@push.rocks/smartmongo';
 
-const myDbInstance = await setupMongoDB();
+const db = new LocalTsmDb({
+  folderPath: './data',    // Required: where to store data
+  port: 27017,             // Optional: defaults to auto-discovery
+  host: '127.0.0.1',       // Optional: bind address
+});
+
+// Start and get connected client
+const client = await db.start();
+
+// Access the underlying server if needed
+const server = db.getServer();
+const uri = db.getConnectionUri();
+
+// Check status
+console.log(db.running); // true
+
+// Stop when done
+await db.stop();
 ```
 
-After invoking `createAndStart`, an instance of MongoDB is spun up and is ready for use. The `createAndStart` function returns a `SmartMongo` instance which can be interacted with for further operations.
+### Features
 
-### Accessing MongoDB Connection Information
+- 🔍 **Auto Port Discovery** — Automatically finds an available port if 27017 is in use
+- 💾 **Automatic Persistence** — Data saved to files, survives restarts
+- 🔌 **Pre-connected Client** — `start()` returns a ready-to-use MongoDB client
+- 🎯 **Zero Config** — Just specify a folder path and you're good to go
 
-After instantiation, you might want to connect your application or test suite to the MongoDB instance. The `getMongoDescriptor` method facilitates this by providing essential connection details.
+## 📖 SmartMongo API
+
+### Creating an Instance
 
 ```typescript
-const mongoDescriptor = await myDbInstance.getMongoDescriptor();
-console.log(mongoDescriptor.mongoDbUrl); // Use this URL to connect with Mongoose or MongoDB clients.
+import { SmartMongo } from '@push.rocks/smartmongo';
+
+// Default: single replica
+const mongo = await SmartMongo.createAndStart();
+
+// Multiple replicas for testing replication
+const mongo = await SmartMongo.createAndStart(3);
 ```
 
-### Stopping and Cleaning Up
-
-Once your tests have completed or you're done using the MongoDB instance, it’s crucial to properly stop and clean up the resources. `@push.rocks/smartmongo` provides two methods for this purpose:
-
-1. **stop()**: Stops the MongoDB instance without persisting any data.
-
-   ```typescript
-   await myDbInstance.stop();
-   ```
-
-2. **stopAndDumpToDir(dirPath)**: Stops the MongoDB instance and persists the data to the specified directory. This is useful if you need to examine the data post-test or reuse it in subsequent runs.
-
-   ```typescript
-   await myDbInstance.stopAndDumpToDir('./path/to/dump');
-   ```
-
-### Advanced Usage
-
-`@push.rocks/smartmongo` also provides advanced features for dumping the database and configuring MongoDB replica sets. These features can be particularly useful for complex testing scenarios or when specific MongoDB behaviors need to be emulated.
-
-#### Dumping Data
-
-To dump the MongoDB data for inspection or backup purposes, use the `stopAndDumpToDir` method. This method optionally takes a function to customize the naming scheme of the dumped files based on the document content.
+### Getting Connection Details
 
 ```typescript
-await myDbInstance.stopAndDumpToDir('./path/to/dump', (doc) => {
-  return `customNameBasedOnDoc-${doc._id}.bson`;
+const descriptor = await mongo.getMongoDescriptor();
+// {
+//   mongoDbName: 'smartmongo_testdatabase',
+//   mongoDbUrl: 'mongodb://127.0.0.1:xxxxx/?replicaSet=testset'
+// }
+```
+
+### Stopping & Cleanup
+
+```typescript
+// Simple stop (data discarded)
+await mongo.stop();
+
+// Stop and dump data to disk for inspection
+await mongo.stopAndDumpToDir('./test-data');
+
+// With custom file naming
+await mongo.stopAndDumpToDir('./test-data', (doc) => `${doc.collection}-${doc._id}.bson`);
+```
+
+## 🔧 TsmDB API
+
+### Server Configuration
+
+```typescript
+import { tsmdb } from '@push.rocks/smartmongo';
+
+const server = new tsmdb.TsmdbServer({
+  port: 27017,           // Default MongoDB port
+  host: '127.0.0.1',     // Bind address
+  storage: 'memory',     // 'memory' or 'file'
+  storagePath: './data', // For file-based storage
+});
+
+await server.start();
+console.log(server.getConnectionUri()); // mongodb://127.0.0.1:27017
+
+// Server properties
+console.log(server.running);              // true
+console.log(server.getUptime());          // seconds
+console.log(server.getConnectionCount()); // active connections
+
+await server.stop();
+```
+
+### Supported MongoDB Operations
+
+TsmDB supports the core MongoDB operations via the wire protocol:
+
+#### 🔹 CRUD Operations
+```typescript
+// Insert
+await collection.insertOne({ name: 'Bob' });
+await collection.insertMany([{ a: 1 }, { a: 2 }]);
+
+// Find
+const doc = await collection.findOne({ name: 'Bob' });
+const docs = await collection.find({ age: { $gte: 18 } }).toArray();
+
+// Update
+await collection.updateOne({ name: 'Bob' }, { $set: { age: 25 } });
+await collection.updateMany({ active: false }, { $set: { archived: true } });
+
+// Delete
+await collection.deleteOne({ name: 'Bob' });
+await collection.deleteMany({ archived: true });
+
+// Replace
+await collection.replaceOne({ _id: id }, { name: 'New Bob', age: 30 });
+
+// Find and Modify
+const result = await collection.findOneAndUpdate(
+  { name: 'Bob' },
+  { $inc: { visits: 1 } },
+  { returnDocument: 'after' }
+);
+```
+
+#### 🔹 Query Operators
+```typescript
+// Comparison
+{ age: { $eq: 25 } }
+{ age: { $ne: 25 } }
+{ age: { $gt: 18, $lt: 65 } }
+{ age: { $gte: 18, $lte: 65 } }
+{ status: { $in: ['active', 'pending'] } }
+{ status: { $nin: ['deleted'] } }
+
+// Logical
+{ $and: [{ age: { $gte: 18 } }, { active: true }] }
+{ $or: [{ status: 'active' }, { admin: true }] }
+{ $not: { status: 'deleted' } }
+
+// Element
+{ email: { $exists: true } }
+{ type: { $type: 'string' } }
+
+// Array
+{ tags: { $all: ['mongodb', 'database'] } }
+{ scores: { $elemMatch: { $gte: 80, $lt: 90 } } }
+{ tags: { $size: 3 } }
+```
+
+#### 🔹 Update Operators
+```typescript
+{ $set: { name: 'New Name' } }
+{ $unset: { tempField: '' } }
+{ $inc: { count: 1 } }
+{ $mul: { price: 1.1 } }
+{ $min: { lowScore: 50 } }
+{ $max: { highScore: 100 } }
+{ $push: { tags: 'new-tag' } }
+{ $pull: { tags: 'old-tag' } }
+{ $addToSet: { tags: 'unique-tag' } }
+{ $pop: { queue: 1 } }  // Remove last
+{ $pop: { queue: -1 } } // Remove first
+```
+
+#### 🔹 Aggregation Pipeline
+```typescript
+const results = await collection.aggregate([
+  { $match: { status: 'active' } },
+  { $group: { _id: '$category', total: { $sum: '$amount' } } },
+  { $sort: { total: -1 } },
+  { $limit: 10 },
+  { $project: { category: '$_id', total: 1, _id: 0 } }
+]).toArray();
+```
+
+Supported stages: `$match`, `$project`, `$group`, `$sort`, `$limit`, `$skip`, `$unwind`, `$lookup`, `$addFields`, `$count`, `$facet`, and more.
+
+#### 🔹 Index Operations
+```typescript
+await collection.createIndex({ email: 1 }, { unique: true });
+await collection.createIndex({ name: 1, age: -1 });
+const indexes = await collection.listIndexes().toArray();
+await collection.dropIndex('email_1');
+```
+
+#### 🔹 Database Operations
+```typescript
+// List databases
+const dbs = await client.db().admin().listDatabases();
+
+// List collections
+const collections = await db.listCollections().toArray();
+
+// Create/drop collections
+await db.createCollection('newcollection');
+await db.dropCollection('oldcollection');
+
+// Drop database
+await db.dropDatabase();
+```
+
+#### 🔹 Count & Distinct
+```typescript
+// Count documents
+const total = await collection.countDocuments({});
+const active = await collection.countDocuments({ status: 'active' });
+const estimated = await collection.estimatedDocumentCount();
+
+// Distinct values
+const departments = await collection.distinct('department');
+const activeDepts = await collection.distinct('department', { status: 'active' });
+```
+
+#### 🔹 Bulk Operations
+```typescript
+const result = await collection.bulkWrite([
+  { insertOne: { document: { name: 'Bulk1' } } },
+  { updateOne: { filter: { name: 'John' }, update: { $set: { bulk: true } } } },
+  { deleteOne: { filter: { name: 'Expired' } } },
+  { replaceOne: { filter: { _id: id }, replacement: { name: 'Replaced' } } }
+]);
+
+console.log(result.insertedCount);  // 1
+console.log(result.modifiedCount);  // 1
+console.log(result.deletedCount);   // 1
+```
+
+### Storage Adapters
+
+TsmDB supports pluggable storage with data integrity features:
+
+```typescript
+// In-memory (default) - fast, data lost on stop
+const server = new tsmdb.TsmdbServer({ storage: 'memory' });
+
+// In-memory with persistence - periodic snapshots to disk
+const server = new tsmdb.TsmdbServer({
+  storage: 'memory',
+  persistPath: './data/snapshot.json',
+  persistIntervalMs: 30000  // Save every 30 seconds
+});
+
+// File-based - persistent storage with optional checksums
+import { tsmdb } from '@push.rocks/smartmongo';
+
+const server = new tsmdb.TsmdbServer({
+  storage: 'file',
+  storagePath: './data/tsmdb'
 });
 ```
 
-Using `@push.rocks/smartmongo` significantly simplifies the process of managing MongoDB instances for local testing environments. It abstracts away the complexity of starting, operating, and tearing down MongoDB replica sets, allowing developers to focus on building and testing their applications.
+## ⚡ Performance & Reliability Features
 
-### Conclusion
+TsmDB includes enterprise-grade features for robustness:
 
-`@push.rocks/smartmongo` serves as a powerful tool in a developer's arsenal for efficiently configuring, running, and managing MongoDB instances in testing scenarios. By following the above guide, developers can leverage MongoDB in their projects with minimal setup and gain valuable insights into their applications' data interactions in a controlled and reproducible environment.
+### 🔍 Index-Accelerated Queries
+
+Indexes are automatically used to accelerate queries. Instead of scanning all documents, TsmDB uses:
+
+- **Hash indexes** for equality queries (`$eq`, `$in`)
+- **B-tree indexes** for range queries (`$gt`, `$gte`, `$lt`, `$lte`)
+
+```typescript
+// Create an index
+await collection.createIndex({ email: 1 });
+await collection.createIndex({ age: 1 });
+
+// These queries will use the index (fast!)
+await collection.findOne({ email: 'alice@example.com' }); // Uses hash lookup
+await collection.find({ age: { $gte: 18, $lt: 65 } });    // Uses B-tree range scan
+```
+
+### 📊 Query Planner
+
+TsmDB includes a query planner that analyzes queries and selects optimal execution strategies:
+
+```typescript
+import { tsmdb } from '@push.rocks/smartmongo';
+
+// For debugging, you can access the query planner
+const planner = new tsmdb.QueryPlanner(indexEngine);
+const plan = await planner.plan(filter);
+
+console.log(plan);
+// {
+//   type: 'IXSCAN',           // or 'IXSCAN_RANGE', 'COLLSCAN'
+//   indexName: 'email_1',
+//   selectivity: 0.01,
+//   indexCovering: true
+// }
+```
+
+### 📝 Write-Ahead Logging (WAL)
+
+For durability, TsmDB supports write-ahead logging:
+
+```typescript
+import { tsmdb } from '@push.rocks/smartmongo';
+
+const wal = new tsmdb.WAL('./data/wal.log');
+await wal.initialize();
+
+// WAL entries include:
+// - LSN (Log Sequence Number)
+// - Timestamp
+// - Operation type (insert, update, delete, checkpoint)
+// - Document data (BSON serialized)
+// - CRC32 checksum for integrity
+
+// Recovery support
+const entries = wal.getEntriesAfter(lastCheckpointLsn);
+```
+
+### 🔐 Session Management
+
+TsmDB tracks client sessions with automatic timeout and transaction linking:
+
+```typescript
+// Sessions are automatically managed when using the MongoDB driver
+const session = client.startSession();
+
+try {
+  session.startTransaction();
+  await collection.insertOne({ name: 'Alice' }, { session });
+  await collection.updateOne({ name: 'Bob' }, { $inc: { balance: 100 } }, { session });
+  await session.commitTransaction();
+} catch (error) {
+  await session.abortTransaction();
+} finally {
+  session.endSession();
+}
+
+// Session features:
+// - Automatic session timeout (30 minutes default)
+// - Transaction auto-abort on session expiry
+// - Session activity tracking
+```
+
+### ✅ Data Integrity Checksums
+
+File-based storage supports CRC32 checksums to detect corruption:
+
+```typescript
+import { tsmdb } from '@push.rocks/smartmongo';
+
+// Checksums are used internally for WAL and data integrity
+// Documents are checksummed on write, verified on read
+```
+
+### 📋 Supported Wire Protocol Commands
+
+| Category | Commands |
+|----------|----------|
+| **Handshake** | `hello`, `isMaster` |
+| **CRUD** | `find`, `insert`, `update`, `delete`, `findAndModify`, `getMore`, `killCursors` |
+| **Aggregation** | `aggregate`, `count`, `distinct` |
+| **Indexes** | `createIndexes`, `dropIndexes`, `listIndexes` |
+| **Transactions** | `startTransaction`, `commitTransaction`, `abortTransaction` |
+| **Sessions** | `startSession`, `endSessions` |
+| **Admin** | `ping`, `listDatabases`, `listCollections`, `drop`, `dropDatabase`, `create`, `serverStatus`, `buildInfo`, `dbStats`, `collStats` |
+
+TsmDB supports MongoDB wire protocol versions 0-21, compatible with MongoDB 3.6 through 7.0 drivers.
+
+## 🧪 Testing Examples
+
+### Jest/Mocha with LocalTsmDb
+
+```typescript
+import { LocalTsmDb } from '@push.rocks/smartmongo';
+import { MongoClient, Db } from 'mongodb';
+
+let db: LocalTsmDb;
+let client: MongoClient;
+
+beforeAll(async () => {
+  db = new LocalTsmDb({ folderPath: './test-data' });
+  client = await db.start();
+});
+
+afterAll(async () => {
+  await db.stop();
+});
+
+beforeEach(async () => {
+  // Clean slate for each test
+  await client.db('test').dropDatabase();
+});
+
+test('should insert and find user', async () => {
+  const users = client.db('test').collection('users');
+  await users.insertOne({ name: 'Alice', email: 'alice@example.com' });
+
+  const user = await users.findOne({ name: 'Alice' });
+  expect(user?.email).toBe('alice@example.com');
+});
+```
+
+### Jest/Mocha with TsmDB
+
+```typescript
+import { tsmdb } from '@push.rocks/smartmongo';
+import { MongoClient, Db } from 'mongodb';
+
+let server: tsmdb.TsmdbServer;
+let client: MongoClient;
+let testDb: Db;
+
+beforeAll(async () => {
+  server = new tsmdb.TsmdbServer({ port: 27117 });
+  await server.start();
+
+  client = new MongoClient('mongodb://127.0.0.1:27117');
+  await client.connect();
+  testDb = client.db('test');
+});
+
+afterAll(async () => {
+  await client.close();
+  await server.stop();
+});
+
+beforeEach(async () => {
+  await testDb.dropDatabase();
+});
+
+test('should insert and find user', async () => {
+  const users = testDb.collection('users');
+  await users.insertOne({ name: 'Alice', email: 'alice@example.com' });
+
+  const user = await users.findOne({ name: 'Alice' });
+  expect(user?.email).toBe('alice@example.com');
+});
+```
+
+### With @push.rocks/tapbundle
+
+```typescript
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import { LocalTsmDb } from '@push.rocks/smartmongo';
+
+let db: LocalTsmDb;
+
+tap.test('setup', async () => {
+  db = new LocalTsmDb({ folderPath: './test-data' });
+  await db.start();
+});
+
+tap.test('should perform CRUD operations', async () => {
+  const client = db.getClient();
+  const col = client.db('test').collection('items');
+
+  // Create
+  const result = await col.insertOne({ name: 'Widget', price: 9.99 });
+  expect(result.insertedId).toBeTruthy();
+
+  // Read
+  const item = await col.findOne({ name: 'Widget' });
+  expect(item?.price).toEqual(9.99);
+
+  // Update
+  await col.updateOne({ name: 'Widget' }, { $set: { price: 12.99 } });
+  const updated = await col.findOne({ name: 'Widget' });
+  expect(updated?.price).toEqual(12.99);
+
+  // Delete
+  await col.deleteOne({ name: 'Widget' });
+  const deleted = await col.findOne({ name: 'Widget' });
+  expect(deleted).toBeNull();
+});
+
+tap.test('teardown', async () => {
+  await db.stop();
+});
+
+export default tap.start();
+```
+
+## 🏗️ Architecture
+
+### Module Structure
+
+```
+@push.rocks/smartmongo
+├── SmartMongo      → Real MongoDB memory server (mongodb-memory-server wrapper)
+├── tsmdb           → Wire protocol server with full engine stack
+└── LocalTsmDb      → Zero-config local database (convenience wrapper)
+```
+
+### TsmDB Wire Protocol Stack
+
+```
+┌─────────────────────────────────────────────────────────────┐
+│                   Official MongoDB Driver                    │
+│                      (mongodb npm)                          │
+└─────────────────────────┬───────────────────────────────────┘
+                          │ TCP + OP_MSG/BSON
+                          ▼
+┌─────────────────────────────────────────────────────────────┐
+│                      TsmdbServer                            │
+│  ┌──────────────┐  ┌──────────────┐  ┌──────────────────┐  │
+│  │ WireProtocol │→ │CommandRouter │→ │     Handlers     │  │
+│  │  (OP_MSG)    │  │              │  │ (Find, Insert..) │  │
+│  └──────────────┘  └──────────────┘  └──────────────────┘  │
+└─────────────────────────┬───────────────────────────────────┘
+                          │
+                          ▼
+┌─────────────────────────────────────────────────────────────┐
+│                       Engines                               │
+│  ┌─────────┐ ┌────────┐ ┌───────────┐ ┌───────┐ ┌───────┐ │
+│  │ Query   │ │ Update │ │Aggregation│ │ Index │ │Session│ │
+│  │ Planner │ │ Engine │ │  Engine   │ │Engine │ │Engine │ │
+│  └─────────┘ └────────┘ └───────────┘ └───────┘ └───────┘ │
+│                   ┌──────────────────────┐                  │
+│                   │ Transaction Engine   │                  │
+│                   └──────────────────────┘                  │
+└─────────────────────────┬───────────────────────────────────┘
+                          │
+                          ▼
+┌─────────────────────────────────────────────────────────────┐
+│                   Storage Layer                              │
+│  ┌──────────────────┐  ┌──────────────────┐  ┌──────────┐  │
+│  │  MemoryStorage   │  │   FileStorage    │  │   WAL    │  │
+│  │                  │  │  (+ Checksums)   │  │          │  │
+│  └──────────────────┘  └──────────────────┘  └──────────┘  │
+└─────────────────────────────────────────────────────────────┘
+```
+
+### Key Components
+
+| Component | Description |
+|-----------|-------------|
+| **WireProtocol** | Parses MongoDB OP_MSG binary protocol |
+| **CommandRouter** | Routes commands to appropriate handlers |
+| **QueryPlanner** | Analyzes queries and selects execution strategy |
+| **IndexEngine** | Manages B-tree and hash indexes |
+| **SessionEngine** | Tracks client sessions and timeouts |
+| **TransactionEngine** | Handles ACID transaction semantics |
+| **WAL** | Write-ahead logging for durability |
 
 ## License and Legal Information
 
-This repository contains open-source code that is licensed under the MIT License. A copy of the MIT License can be found in the [license](license) file within this repository.
+This repository contains open-source code licensed under the MIT License. A copy of the license can be found in the [LICENSE](./LICENSE) file.
 
 **Please note:** The MIT License does not grant permission to use the trade names, trademarks, service marks, or product names of the project, except as required for reasonable and customary use in describing the origin of the work and reproducing the content of the NOTICE file.
 
 ### Trademarks
 
-This project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH and are not included within the scope of the MIT license granted herein. Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines, and any usage must be approved in writing by Task Venture Capital GmbH.
+This project is owned and maintained by Task Venture Capital GmbH. The names and logos associated with Task Venture Capital GmbH and any related products or services are trademarks of Task Venture Capital GmbH or third parties, and are not included within the scope of the MIT license granted herein.
+
+Use of these trademarks must comply with Task Venture Capital GmbH's Trademark Guidelines or the guidelines of the respective third-party owners, and any usage must be approved in writing. Third-party trademarks used herein are the property of their respective owners and used only in a descriptive manner, e.g. for an implementation of an API or similar.
 
 ### Company Information
 
 Task Venture Capital GmbH
-Registered at District court Bremen HRB 35230 HB, Germany
+Registered at District Court Bremen HRB 35230 HB, Germany
 
-For any legal inquiries or if you require further information, please contact us via email at hello@task.vc.
+For any legal inquiries or further information, please contact us via email at hello@task.vc.
 
 By using this repository, you acknowledge that you have read this section, agree to comply with its terms, and understand that the licensing of the code does not imply endorsement by Task Venture Capital GmbH of any derivative works.

test/test.tsmdb.checksum.ts

@@ -0,0 +1,232 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as smartmongo from '../ts/index.js';
+
+const {
+  calculateCRC32,
+  calculateCRC32Buffer,
+  calculateDocumentChecksum,
+  addChecksum,
+  verifyChecksum,
+  removeChecksum,
+} = smartmongo.tsmdb;
+
+// ============================================================================
+// CRC32 String Tests
+// ============================================================================
+
+tap.test('checksum: calculateCRC32 should return consistent value for same input', async () => {
+  const result1 = calculateCRC32('hello world');
+  const result2 = calculateCRC32('hello world');
+  expect(result1).toEqual(result2);
+});
+
+tap.test('checksum: calculateCRC32 should return different values for different inputs', async () => {
+  const result1 = calculateCRC32('hello');
+  const result2 = calculateCRC32('world');
+  expect(result1).not.toEqual(result2);
+});
+
+tap.test('checksum: calculateCRC32 should return a 32-bit unsigned integer', async () => {
+  const result = calculateCRC32('test string');
+  expect(result).toBeGreaterThanOrEqual(0);
+  expect(result).toBeLessThanOrEqual(0xFFFFFFFF);
+});
+
+tap.test('checksum: calculateCRC32 should handle empty string', async () => {
+  const result = calculateCRC32('');
+  expect(typeof result).toEqual('number');
+  expect(result).toBeGreaterThanOrEqual(0);
+});
+
+tap.test('checksum: calculateCRC32 should handle special characters', async () => {
+  const result = calculateCRC32('hello\nworld\t!"#$%&\'()');
+  expect(typeof result).toEqual('number');
+  expect(result).toBeGreaterThanOrEqual(0);
+});
+
+tap.test('checksum: calculateCRC32 should handle unicode characters', async () => {
+  const result = calculateCRC32('hello 世界 🌍');
+  expect(typeof result).toEqual('number');
+  expect(result).toBeGreaterThanOrEqual(0);
+});
+
+// ============================================================================
+// CRC32 Buffer Tests
+// ============================================================================
+
+tap.test('checksum: calculateCRC32Buffer should return consistent value for same input', async () => {
+  const buffer = Buffer.from('hello world');
+  const result1 = calculateCRC32Buffer(buffer);
+  const result2 = calculateCRC32Buffer(buffer);
+  expect(result1).toEqual(result2);
+});
+
+tap.test('checksum: calculateCRC32Buffer should return different values for different inputs', async () => {
+  const buffer1 = Buffer.from('hello');
+  const buffer2 = Buffer.from('world');
+  const result1 = calculateCRC32Buffer(buffer1);
+  const result2 = calculateCRC32Buffer(buffer2);
+  expect(result1).not.toEqual(result2);
+});
+
+tap.test('checksum: calculateCRC32Buffer should handle empty buffer', async () => {
+  const result = calculateCRC32Buffer(Buffer.from(''));
+  expect(typeof result).toEqual('number');
+  expect(result).toBeGreaterThanOrEqual(0);
+});
+
+tap.test('checksum: calculateCRC32Buffer should handle binary data', async () => {
+  const buffer = Buffer.from([0x00, 0xFF, 0x7F, 0x80, 0x01]);
+  const result = calculateCRC32Buffer(buffer);
+  expect(typeof result).toEqual('number');
+  expect(result).toBeGreaterThanOrEqual(0);
+});
+
+// ============================================================================
+// Document Checksum Tests
+// ============================================================================
+
+tap.test('checksum: calculateDocumentChecksum should return consistent value', async () => {
+  const doc = { name: 'John', age: 30 };
+  const result1 = calculateDocumentChecksum(doc);
+  const result2 = calculateDocumentChecksum(doc);
+  expect(result1).toEqual(result2);
+});
+
+tap.test('checksum: calculateDocumentChecksum should exclude _checksum field', async () => {
+  const doc1 = { name: 'John', age: 30 };
+  const doc2 = { name: 'John', age: 30, _checksum: 12345 };
+  const result1 = calculateDocumentChecksum(doc1);
+  const result2 = calculateDocumentChecksum(doc2);
+  expect(result1).toEqual(result2);
+});
+
+tap.test('checksum: calculateDocumentChecksum should handle empty document', async () => {
+  const result = calculateDocumentChecksum({});
+  expect(typeof result).toEqual('number');
+  expect(result).toBeGreaterThanOrEqual(0);
+});
+
+tap.test('checksum: calculateDocumentChecksum should handle nested objects', async () => {
+  const doc = {
+    name: 'John',
+    address: {
+      street: '123 Main St',
+      city: 'Springfield',
+      zip: {
+        code: '12345',
+        plus4: '6789',
+      },
+    },
+  };
+  const result = calculateDocumentChecksum(doc);
+  expect(typeof result).toEqual('number');
+  expect(result).toBeGreaterThanOrEqual(0);
+});
+
+tap.test('checksum: calculateDocumentChecksum should handle arrays', async () => {
+  const doc = {
+    name: 'John',
+    tags: ['developer', 'tester', 'admin'],
+    scores: [95, 87, 92],
+  };
+  const result = calculateDocumentChecksum(doc);
+  expect(typeof result).toEqual('number');
+  expect(result).toBeGreaterThanOrEqual(0);
+});
+
+// ============================================================================
+// Add/Verify/Remove Checksum Tests
+// ============================================================================
+
+tap.test('checksum: addChecksum should add _checksum field to document', async () => {
+  const doc = { name: 'John', age: 30 };
+  const docWithChecksum = addChecksum(doc);
+
+  expect('_checksum' in docWithChecksum).toBeTrue();
+  expect(typeof docWithChecksum._checksum).toEqual('number');
+  expect(docWithChecksum.name).toEqual('John');
+  expect(docWithChecksum.age).toEqual(30);
+});
+
+tap.test('checksum: addChecksum should not modify the original document', async () => {
+  const doc = { name: 'John', age: 30 };
+  addChecksum(doc);
+  expect('_checksum' in doc).toBeFalse();
+});
+
+tap.test('checksum: verifyChecksum should return true for valid checksum', async () => {
+  const doc = { name: 'John', age: 30 };
+  const docWithChecksum = addChecksum(doc);
+  const isValid = verifyChecksum(docWithChecksum);
+  expect(isValid).toBeTrue();
+});
+
+tap.test('checksum: verifyChecksum should return false for tampered document', async () => {
+  const doc = { name: 'John', age: 30 };
+  const docWithChecksum = addChecksum(doc);
+
+  // Tamper with the document
+  docWithChecksum.age = 31;
+
+  const isValid = verifyChecksum(docWithChecksum);
+  expect(isValid).toBeFalse();
+});
+
+tap.test('checksum: verifyChecksum should return false for wrong checksum', async () => {
+  const doc = { name: 'John', age: 30, _checksum: 12345 };
+  const isValid = verifyChecksum(doc);
+  expect(isValid).toBeFalse();
+});
+
+tap.test('checksum: verifyChecksum should return true for document without checksum', async () => {
+  const doc = { name: 'John', age: 30 };
+  const isValid = verifyChecksum(doc);
+  expect(isValid).toBeTrue();
+});
+
+tap.test('checksum: removeChecksum should remove _checksum field', async () => {
+  const doc = { name: 'John', age: 30 };
+  const docWithChecksum = addChecksum(doc);
+  const docWithoutChecksum = removeChecksum(docWithChecksum);
+
+  expect('_checksum' in docWithoutChecksum).toBeFalse();
+  expect(docWithoutChecksum.name).toEqual('John');
+  expect(docWithoutChecksum.age).toEqual(30);
+});
+
+tap.test('checksum: removeChecksum should handle document without checksum', async () => {
+  const doc = { name: 'John', age: 30 };
+  const result = removeChecksum(doc);
+
+  expect('_checksum' in result).toBeFalse();
+  expect(result.name).toEqual('John');
+  expect(result.age).toEqual(30);
+});
+
+// ============================================================================
+// Round-trip Tests
+// ============================================================================
+
+tap.test('checksum: full round-trip - add, verify, remove', async () => {
+  const original = { name: 'Test', value: 42, nested: { a: 1, b: 2 } };
+
+  // Add checksum
+  const withChecksum = addChecksum(original);
+  expect('_checksum' in withChecksum).toBeTrue();
+
+  // Verify checksum
+  expect(verifyChecksum(withChecksum)).toBeTrue();
+
+  // Remove checksum
+  const restored = removeChecksum(withChecksum);
+  expect('_checksum' in restored).toBeFalse();
+
+  // Original data should be intact
+  expect(restored.name).toEqual('Test');
+  expect(restored.value).toEqual(42);
+  expect(restored.nested.a).toEqual(1);
+  expect(restored.nested.b).toEqual(2);
+});
+
+export default tap.start();

test/test.tsmdb.indexengine.ts

@@ -0,0 +1,417 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as smartmongo from '../ts/index.js';
+
+const { IndexEngine, MemoryStorageAdapter, ObjectId } = smartmongo.tsmdb;
+
+let storage: InstanceType<typeof MemoryStorageAdapter>;
+let indexEngine: InstanceType<typeof IndexEngine>;
+
+const TEST_DB = 'testdb';
+const TEST_COLL = 'indextest';
+
+// ============================================================================
+// Setup
+// ============================================================================
+
+tap.test('indexengine: should create IndexEngine instance', async () => {
+  storage = new MemoryStorageAdapter();
+  await storage.initialize();
+  await storage.createCollection(TEST_DB, TEST_COLL);
+
+  indexEngine = new IndexEngine(TEST_DB, TEST_COLL, storage);
+  expect(indexEngine).toBeTruthy();
+});
+
+// ============================================================================
+// Index Creation Tests
+// ============================================================================
+
+tap.test('indexengine: createIndex should create single-field index', async () => {
+  const indexName = await indexEngine.createIndex({ name: 1 });
+
+  expect(indexName).toEqual('name_1');
+
+  const exists = await indexEngine.indexExists('name_1');
+  expect(exists).toBeTrue();
+});
+
+tap.test('indexengine: createIndex should create compound index', async () => {
+  const indexName = await indexEngine.createIndex({ city: 1, state: -1 });
+
+  expect(indexName).toEqual('city_1_state_-1');
+
+  const exists = await indexEngine.indexExists('city_1_state_-1');
+  expect(exists).toBeTrue();
+});
+
+tap.test('indexengine: createIndex should use custom name if provided', async () => {
+  const indexName = await indexEngine.createIndex({ email: 1 }, { name: 'custom_email_index' });
+
+  expect(indexName).toEqual('custom_email_index');
+
+  const exists = await indexEngine.indexExists('custom_email_index');
+  expect(exists).toBeTrue();
+});
+
+tap.test('indexengine: createIndex should handle unique option', async () => {
+  const indexName = await indexEngine.createIndex({ uniqueField: 1 }, { unique: true });
+
+  expect(indexName).toEqual('uniqueField_1');
+
+  const indexes = await indexEngine.listIndexes();
+  const uniqueIndex = indexes.find(i => i.name === 'uniqueField_1');
+  expect(uniqueIndex!.unique).toBeTrue();
+});
+
+tap.test('indexengine: createIndex should handle sparse option', async () => {
+  const indexName = await indexEngine.createIndex({ sparseField: 1 }, { sparse: true });
+
+  expect(indexName).toEqual('sparseField_1');
+
+  const indexes = await indexEngine.listIndexes();
+  const sparseIndex = indexes.find(i => i.name === 'sparseField_1');
+  expect(sparseIndex!.sparse).toBeTrue();
+});
+
+tap.test('indexengine: createIndex should return existing index name if already exists', async () => {
+  const indexName1 = await indexEngine.createIndex({ existingField: 1 }, { name: 'existing_idx' });
+  const indexName2 = await indexEngine.createIndex({ existingField: 1 }, { name: 'existing_idx' });
+
+  expect(indexName1).toEqual(indexName2);
+});
+
+// ============================================================================
+// Index Listing and Existence Tests
+// ============================================================================
+
+tap.test('indexengine: listIndexes should return all indexes', async () => {
+  const indexes = await indexEngine.listIndexes();
+
+  expect(indexes.length).toBeGreaterThanOrEqual(5); // _id_ + created indexes
+  expect(indexes.some(i => i.name === '_id_')).toBeTrue();
+  expect(indexes.some(i => i.name === 'name_1')).toBeTrue();
+});
+
+tap.test('indexengine: indexExists should return true for existing index', async () => {
+  const exists = await indexEngine.indexExists('name_1');
+  expect(exists).toBeTrue();
+});
+
+tap.test('indexengine: indexExists should return false for non-existent index', async () => {
+  const exists = await indexEngine.indexExists('nonexistent_index');
+  expect(exists).toBeFalse();
+});
+
+// ============================================================================
+// Document Operations and Index Updates
+// ============================================================================
+
+tap.test('indexengine: should insert documents for index testing', async () => {
+  // Create a fresh index engine for document operations
+  await storage.dropCollection(TEST_DB, TEST_COLL);
+  await storage.createCollection(TEST_DB, TEST_COLL);
+
+  indexEngine = new IndexEngine(TEST_DB, TEST_COLL, storage);
+
+  // Create indexes first
+  await indexEngine.createIndex({ age: 1 });
+  await indexEngine.createIndex({ category: 1 });
+
+  // Insert test documents
+  const docs = [
+    { _id: new ObjectId(), name: 'Alice', age: 25, category: 'A' },
+    { _id: new ObjectId(), name: 'Bob', age: 30, category: 'B' },
+    { _id: new ObjectId(), name: 'Charlie', age: 35, category: 'A' },
+    { _id: new ObjectId(), name: 'Diana', age: 28, category: 'C' },
+    { _id: new ObjectId(), name: 'Eve', age: 30, category: 'B' },
+  ];
+
+  for (const doc of docs) {
+    const stored = await storage.insertOne(TEST_DB, TEST_COLL, doc);
+    await indexEngine.onInsert(stored);
+  }
+});
+
+tap.test('indexengine: onInsert should update indexes', async () => {
+  const newDoc = {
+    _id: new ObjectId(),
+    name: 'Frank',
+    age: 40,
+    category: 'D',
+  };
+
+  const stored = await storage.insertOne(TEST_DB, TEST_COLL, newDoc);
+  await indexEngine.onInsert(stored);
+
+  // Find by the indexed field
+  const candidates = await indexEngine.findCandidateIds({ age: 40 });
+  expect(candidates).toBeTruthy();
+  expect(candidates!.size).toEqual(1);
+});
+
+tap.test('indexengine: onUpdate should update indexes correctly', async () => {
+  // Get an existing document
+  const docs = await storage.findAll(TEST_DB, TEST_COLL);
+  const oldDoc = docs.find(d => d.name === 'Alice')!;
+
+  // Update the document
+  const newDoc = { ...oldDoc, age: 26 };
+  await storage.updateById(TEST_DB, TEST_COLL, oldDoc._id, newDoc);
+  await indexEngine.onUpdate(oldDoc, newDoc);
+
+  // Old value should not be in index
+  const oldCandidates = await indexEngine.findCandidateIds({ age: 25 });
+  expect(oldCandidates).toBeTruthy();
+  expect(oldCandidates!.has(oldDoc._id.toHexString())).toBeFalse();
+
+  // New value should be in index
+  const newCandidates = await indexEngine.findCandidateIds({ age: 26 });
+  expect(newCandidates).toBeTruthy();
+  expect(newCandidates!.has(oldDoc._id.toHexString())).toBeTrue();
+});
+
+tap.test('indexengine: onDelete should remove from indexes', async () => {
+  const docs = await storage.findAll(TEST_DB, TEST_COLL);
+  const docToDelete = docs.find(d => d.name === 'Frank')!;
+
+  await storage.deleteById(TEST_DB, TEST_COLL, docToDelete._id);
+  await indexEngine.onDelete(docToDelete);
+
+  const candidates = await indexEngine.findCandidateIds({ age: 40 });
+  expect(candidates).toBeTruthy();
+  expect(candidates!.has(docToDelete._id.toHexString())).toBeFalse();
+});
+
+// ============================================================================
+// findCandidateIds Tests
+// ============================================================================
+
+tap.test('indexengine: findCandidateIds with equality filter', async () => {
+  const candidates = await indexEngine.findCandidateIds({ age: 30 });
+
+  expect(candidates).toBeTruthy();
+  expect(candidates!.size).toEqual(2); // Bob and Eve both have age 30
+});
+
+tap.test('indexengine: findCandidateIds with $in filter', async () => {
+  const candidates = await indexEngine.findCandidateIds({ age: { $in: [28, 30] } });
+
+  expect(candidates).toBeTruthy();
+  expect(candidates!.size).toEqual(3); // Diana (28), Bob (30), Eve (30)
+});
+
+tap.test('indexengine: findCandidateIds with no matching index', async () => {
+  const candidates = await indexEngine.findCandidateIds({ nonIndexedField: 'value' });
+
+  // Should return null when no index can be used
+  expect(candidates).toBeNull();
+});
+
+tap.test('indexengine: findCandidateIds with empty filter', async () => {
+  const candidates = await indexEngine.findCandidateIds({});
+
+  // Empty filter = no index can be used
+  expect(candidates).toBeNull();
+});
+
+// ============================================================================
+// Range Query Tests (B-Tree)
+// ============================================================================
+
+tap.test('indexengine: findCandidateIds with $gt', async () => {
+  const candidates = await indexEngine.findCandidateIds({ age: { $gt: 30 } });
+
+  expect(candidates).toBeTruthy();
+  // Charlie (35) is > 30
+  expect(candidates!.size).toBeGreaterThanOrEqual(1);
+});
+
+tap.test('indexengine: findCandidateIds with $lt', async () => {
+  const candidates = await indexEngine.findCandidateIds({ age: { $lt: 28 } });
+
+  expect(candidates).toBeTruthy();
+  // Alice (26) is < 28
+  expect(candidates!.size).toBeGreaterThanOrEqual(1);
+});
+
+tap.test('indexengine: findCandidateIds with $gte', async () => {
+  const candidates = await indexEngine.findCandidateIds({ age: { $gte: 30 } });
+
+  expect(candidates).toBeTruthy();
+  // Bob (30), Eve (30), Charlie (35)
+  expect(candidates!.size).toBeGreaterThanOrEqual(3);
+});
+
+tap.test('indexengine: findCandidateIds with $lte', async () => {
+  const candidates = await indexEngine.findCandidateIds({ age: { $lte: 28 } });
+
+  expect(candidates).toBeTruthy();
+  // Alice (26), Diana (28)
+  expect(candidates!.size).toBeGreaterThanOrEqual(2);
+});
+
+tap.test('indexengine: findCandidateIds with range $gt and $lt', async () => {
+  const candidates = await indexEngine.findCandidateIds({ age: { $gt: 26, $lt: 35 } });
+
+  expect(candidates).toBeTruthy();
+  // Diana (28), Bob (30), Eve (30) are between 26 and 35 exclusive
+  expect(candidates!.size).toBeGreaterThanOrEqual(3);
+});
+
+// ============================================================================
+// Index Selection Tests
+// ============================================================================
+
+tap.test('indexengine: selectIndex should return best index for equality', async () => {
+  const result = indexEngine.selectIndex({ age: 30 });
+
+  expect(result).toBeTruthy();
+  expect(result!.name).toEqual('age_1');
+});
+
+tap.test('indexengine: selectIndex should return best index for range query', async () => {
+  const result = indexEngine.selectIndex({ age: { $gt: 25 } });
+
+  expect(result).toBeTruthy();
+  expect(result!.name).toEqual('age_1');
+});
+
+tap.test('indexengine: selectIndex should return null for no matching filter', async () => {
+  const result = indexEngine.selectIndex({ nonIndexedField: 'value' });
+
+  expect(result).toBeNull();
+});
+
+tap.test('indexengine: selectIndex should return null for empty filter', async () => {
+  const result = indexEngine.selectIndex({});
+
+  expect(result).toBeNull();
+});
+
+tap.test('indexengine: selectIndex should prefer more specific indexes', async () => {
+  // Create a compound index
+  await indexEngine.createIndex({ age: 1, category: 1 }, { name: 'age_category_compound' });
+
+  // Query that matches compound index
+  const result = indexEngine.selectIndex({ age: 30, category: 'B' });
+
+  expect(result).toBeTruthy();
+  // Should prefer the compound index since it covers more fields
+  expect(result!.name).toEqual('age_category_compound');
+});
+
+// ============================================================================
+// Drop Index Tests
+// ============================================================================
+
+tap.test('indexengine: dropIndex should remove the index', async () => {
+  await indexEngine.createIndex({ dropTest: 1 }, { name: 'drop_test_idx' });
+  expect(await indexEngine.indexExists('drop_test_idx')).toBeTrue();
+
+  await indexEngine.dropIndex('drop_test_idx');
+  expect(await indexEngine.indexExists('drop_test_idx')).toBeFalse();
+});
+
+tap.test('indexengine: dropIndex should throw for _id index', async () => {
+  let threw = false;
+  try {
+    await indexEngine.dropIndex('_id_');
+  } catch (e) {
+    threw = true;
+  }
+  expect(threw).toBeTrue();
+});
+
+tap.test('indexengine: dropIndex should throw for non-existent index', async () => {
+  let threw = false;
+  try {
+    await indexEngine.dropIndex('nonexistent_index');
+  } catch (e) {
+    threw = true;
+  }
+  expect(threw).toBeTrue();
+});
+
+tap.test('indexengine: dropAllIndexes should remove all indexes except _id', async () => {
+  // Create some indexes to drop
+  await indexEngine.createIndex({ toDrop1: 1 });
+  await indexEngine.createIndex({ toDrop2: 1 });
+
+  await indexEngine.dropAllIndexes();
+
+  const indexes = await indexEngine.listIndexes();
+  expect(indexes.length).toEqual(1);
+  expect(indexes[0].name).toEqual('_id_');
+});
+
+// ============================================================================
+// Unique Index Constraint Tests
+// ============================================================================
+
+tap.test('indexengine: unique index should prevent duplicate inserts', async () => {
+  // Create fresh collection
+  await storage.dropCollection(TEST_DB, 'uniquetest');
+  await storage.createCollection(TEST_DB, 'uniquetest');
+
+  const uniqueIndexEngine = new IndexEngine(TEST_DB, 'uniquetest', storage);
+  await uniqueIndexEngine.createIndex({ email: 1 }, { unique: true });
+
+  // Insert first document
+  const doc1 = { _id: new ObjectId(), email: 'test@example.com', name: 'Test' };
+  const stored1 = await storage.insertOne(TEST_DB, 'uniquetest', doc1);
+  await uniqueIndexEngine.onInsert(stored1);
+
+  // Try to insert duplicate
+  const doc2 = { _id: new ObjectId(), email: 'test@example.com', name: 'Test2' };
+  const stored2 = await storage.insertOne(TEST_DB, 'uniquetest', doc2);
+
+  let threw = false;
+  try {
+    await uniqueIndexEngine.onInsert(stored2);
+  } catch (e: any) {
+    threw = true;
+    expect(e.message).toContain('duplicate key');
+  }
+
+  expect(threw).toBeTrue();
+});
+
+// ============================================================================
+// Sparse Index Tests
+// ============================================================================
+
+tap.test('indexengine: sparse index should not include documents without the field', async () => {
+  // Create fresh collection
+  await storage.dropCollection(TEST_DB, 'sparsetest');
+  await storage.createCollection(TEST_DB, 'sparsetest');
+
+  const sparseIndexEngine = new IndexEngine(TEST_DB, 'sparsetest', storage);
+  await sparseIndexEngine.createIndex({ optionalField: 1 }, { sparse: true });
+
+  // Insert doc with the field
+  const doc1 = { _id: new ObjectId(), optionalField: 'hasValue', name: 'HasField' };
+  const stored1 = await storage.insertOne(TEST_DB, 'sparsetest', doc1);
+  await sparseIndexEngine.onInsert(stored1);
+
+  // Insert doc without the field
+  const doc2 = { _id: new ObjectId(), name: 'NoField' };
+  const stored2 = await storage.insertOne(TEST_DB, 'sparsetest', doc2);
+  await sparseIndexEngine.onInsert(stored2);
+
+  // Search for documents with the field
+  const candidates = await sparseIndexEngine.findCandidateIds({ optionalField: 'hasValue' });
+  expect(candidates).toBeTruthy();
+  expect(candidates!.size).toEqual(1);
+  expect(candidates!.has(stored1._id.toHexString())).toBeTrue();
+});
+
+// ============================================================================
+// Cleanup
+// ============================================================================
+
+tap.test('indexengine: cleanup', async () => {
+  await storage.close();
+  expect(true).toBeTrue();
+});
+
+export default tap.start();

test/test.tsmdb.queryplanner.ts

@@ -0,0 +1,273 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as smartmongo from '../ts/index.js';
+
+const { QueryPlanner, IndexEngine, MemoryStorageAdapter, ObjectId } = smartmongo.tsmdb;
+
+let storage: InstanceType<typeof MemoryStorageAdapter>;
+let indexEngine: InstanceType<typeof IndexEngine>;
+let queryPlanner: InstanceType<typeof QueryPlanner>;
+
+const TEST_DB = 'testdb';
+const TEST_COLL = 'testcoll';
+
+// ============================================================================
+// Setup
+// ============================================================================
+
+tap.test('queryplanner: should create QueryPlanner instance', async () => {
+  storage = new MemoryStorageAdapter();
+  await storage.initialize();
+  await storage.createCollection(TEST_DB, TEST_COLL);
+
+  indexEngine = new IndexEngine(TEST_DB, TEST_COLL, storage);
+  queryPlanner = new QueryPlanner(indexEngine);
+
+  expect(queryPlanner).toBeTruthy();
+});
+
+tap.test('queryplanner: should insert test documents', async () => {
+  // Insert test documents
+  const docs = [
+    { _id: new ObjectId(), name: 'Alice', age: 25, city: 'NYC', category: 'A' },
+    { _id: new ObjectId(), name: 'Bob', age: 30, city: 'LA', category: 'B' },
+    { _id: new ObjectId(), name: 'Charlie', age: 35, city: 'NYC', category: 'A' },
+    { _id: new ObjectId(), name: 'Diana', age: 28, city: 'Chicago', category: 'C' },
+    { _id: new ObjectId(), name: 'Eve', age: 32, city: 'LA', category: 'B' },
+  ];
+
+  for (const doc of docs) {
+    await storage.insertOne(TEST_DB, TEST_COLL, doc);
+  }
+});
+
+// ============================================================================
+// Basic Plan Tests
+// ============================================================================
+
+tap.test('queryplanner: empty filter should result in COLLSCAN', async () => {
+  const plan = await queryPlanner.plan({});
+
+  expect(plan.type).toEqual('COLLSCAN');
+  expect(plan.indexCovering).toBeFalse();
+  expect(plan.selectivity).toEqual(1.0);
+  expect(plan.explanation).toContain('No filter');
+});
+
+tap.test('queryplanner: null filter should result in COLLSCAN', async () => {
+  const plan = await queryPlanner.plan(null as any);
+
+  expect(plan.type).toEqual('COLLSCAN');
+});
+
+tap.test('queryplanner: filter with no matching index should result in COLLSCAN', async () => {
+  const plan = await queryPlanner.plan({ nonExistentField: 'value' });
+
+  expect(plan.type).toEqual('COLLSCAN');
+  expect(plan.explanation).toContain('No suitable index');
+});
+
+// ============================================================================
+// Index Scan Tests (with indexes)
+// ============================================================================
+
+tap.test('queryplanner: should create test indexes', async () => {
+  await indexEngine.createIndex({ age: 1 }, { name: 'age_1' });
+  await indexEngine.createIndex({ name: 1 }, { name: 'name_1' });
+  await indexEngine.createIndex({ city: 1, category: 1 }, { name: 'city_category_1' });
+
+  const indexes = await indexEngine.listIndexes();
+  expect(indexes.length).toBeGreaterThanOrEqual(4); // _id_ + 3 created
+});
+
+tap.test('queryplanner: simple equality filter should use IXSCAN', async () => {
+  const plan = await queryPlanner.plan({ age: 30 });
+
+  expect(plan.type).toEqual('IXSCAN');
+  expect(plan.indexName).toEqual('age_1');
+  expect(plan.indexFieldsUsed).toContain('age');
+  expect(plan.usesRange).toBeFalse();
+});
+
+tap.test('queryplanner: $eq operator should use IXSCAN', async () => {
+  const plan = await queryPlanner.plan({ name: { $eq: 'Alice' } });
+
+  expect(plan.type).toEqual('IXSCAN');
+  expect(plan.indexName).toEqual('name_1');
+  expect(plan.indexFieldsUsed).toContain('name');
+});
+
+tap.test('queryplanner: range filter ($gt) should use IXSCAN_RANGE', async () => {
+  const plan = await queryPlanner.plan({ age: { $gt: 25 } });
+
+  expect(plan.type).toEqual('IXSCAN_RANGE');
+  expect(plan.indexName).toEqual('age_1');
+  expect(plan.usesRange).toBeTrue();
+});
+
+tap.test('queryplanner: range filter ($lt) should use IXSCAN_RANGE', async () => {
+  const plan = await queryPlanner.plan({ age: { $lt: 35 } });
+
+  expect(plan.type).toEqual('IXSCAN_RANGE');
+  expect(plan.usesRange).toBeTrue();
+});
+
+tap.test('queryplanner: range filter ($gte, $lte) should use IXSCAN_RANGE', async () => {
+  const plan = await queryPlanner.plan({ age: { $gte: 25, $lte: 35 } });
+
+  expect(plan.type).toEqual('IXSCAN_RANGE');
+  expect(plan.usesRange).toBeTrue();
+});
+
+tap.test('queryplanner: $in operator should use IXSCAN', async () => {
+  const plan = await queryPlanner.plan({ age: { $in: [25, 30, 35] } });
+
+  expect(plan.type).toEqual('IXSCAN');
+  expect(plan.indexName).toEqual('age_1');
+});
+
+// ============================================================================
+// Compound Index Tests
+// ============================================================================
+
+tap.test('queryplanner: compound index - first field equality should use index', async () => {
+  const plan = await queryPlanner.plan({ city: 'NYC' });
+
+  expect(plan.type).toEqual('IXSCAN');
+  expect(plan.indexName).toEqual('city_category_1');
+  expect(plan.indexFieldsUsed).toContain('city');
+});
+
+tap.test('queryplanner: compound index - both fields should use full index', async () => {
+  const plan = await queryPlanner.plan({ city: 'NYC', category: 'A' });
+
+  expect(plan.type).toEqual('IXSCAN');
+  expect(plan.indexName).toEqual('city_category_1');
+  expect(plan.indexFieldsUsed).toContain('city');
+  expect(plan.indexFieldsUsed).toContain('category');
+  expect(plan.indexFieldsUsed.length).toEqual(2);
+});
+
+// ============================================================================
+// Selectivity Tests
+// ============================================================================
+
+tap.test('queryplanner: equality query should have low selectivity', async () => {
+  const plan = await queryPlanner.plan({ age: 30 });
+
+  expect(plan.selectivity).toBeLessThan(0.1);
+});
+
+tap.test('queryplanner: range query should have moderate selectivity', async () => {
+  const plan = await queryPlanner.plan({ age: { $gt: 25 } });
+
+  expect(plan.selectivity).toBeGreaterThan(0);
+  expect(plan.selectivity).toBeLessThan(1);
+});
+
+tap.test('queryplanner: $in query selectivity depends on array size', async () => {
+  const smallInPlan = await queryPlanner.plan({ age: { $in: [25] } });
+  const largeInPlan = await queryPlanner.plan({ age: { $in: [25, 26, 27, 28, 29, 30] } });
+
+  // Larger $in should have higher selectivity (less selective = more documents)
+  expect(largeInPlan.selectivity).toBeGreaterThanOrEqual(smallInPlan.selectivity);
+});
+
+// ============================================================================
+// Index Covering Tests
+// ============================================================================
+
+tap.test('queryplanner: query covering all filter fields should be index covering', async () => {
+  const plan = await queryPlanner.plan({ age: 30 });
+
+  // All filter fields are covered by the index
+  expect(plan.indexCovering).toBeTrue();
+});
+
+tap.test('queryplanner: query with residual filter should not be index covering', async () => {
+  const plan = await queryPlanner.plan({ city: 'NYC', name: 'Alice' });
+
+  // 'name' is not in the compound index city_category, so it's residual
+  expect(plan.indexCovering).toBeFalse();
+  expect(plan.residualFilter).toBeTruthy();
+});
+
+// ============================================================================
+// Explain Tests
+// ============================================================================
+
+tap.test('queryplanner: explain should return detailed plan info', async () => {
+  const explanation = await queryPlanner.explain({ age: 30 });
+
+  expect(explanation.queryPlanner).toBeTruthy();
+  expect(explanation.queryPlanner.plannerVersion).toEqual(1);
+  expect(explanation.queryPlanner.winningPlan).toBeTruthy();
+  expect(explanation.queryPlanner.rejectedPlans).toBeArray();
+});
+
+tap.test('queryplanner: explain should include winning and rejected plans', async () => {
+  const explanation = await queryPlanner.explain({ age: 30 });
+
+  expect(explanation.queryPlanner.winningPlan.type).toBeTruthy();
+  expect(explanation.queryPlanner.rejectedPlans.length).toBeGreaterThan(0);
+});
+
+tap.test('queryplanner: explain winning plan should be the best plan', async () => {
+  const explanation = await queryPlanner.explain({ age: 30 });
+
+  // Winning plan should use an index, not collection scan (if index exists)
+  expect(explanation.queryPlanner.winningPlan.type).toEqual('IXSCAN');
+
+  // There should be a COLLSCAN in rejected plans
+  const hasCOLLSCAN = explanation.queryPlanner.rejectedPlans.some(p => p.type === 'COLLSCAN');
+  expect(hasCOLLSCAN).toBeTrue();
+});
+
+// ============================================================================
+// $and Operator Tests
+// ============================================================================
+
+tap.test('queryplanner: $and conditions should be analyzed', async () => {
+  const plan = await queryPlanner.plan({
+    $and: [
+      { age: { $gte: 25 } },
+      { age: { $lte: 35 } },
+    ],
+  });
+
+  expect(plan.type).toEqual('IXSCAN_RANGE');
+  expect(plan.indexName).toEqual('age_1');
+});
+
+// ============================================================================
+// Edge Cases
+// ============================================================================
+
+tap.test('queryplanner: should handle complex nested operators', async () => {
+  const plan = await queryPlanner.plan({
+    age: { $gte: 20, $lte: 40 },
+    city: 'NYC',
+  });
+
+  expect(plan).toBeTruthy();
+  expect(plan.type).not.toBeUndefined();
+});
+
+tap.test('queryplanner: should handle $exists operator', async () => {
+  await indexEngine.createIndex({ email: 1 }, { name: 'email_1', sparse: true });
+
+  const plan = await queryPlanner.plan({ email: { $exists: true } });
+
+  // $exists can use sparse indexes
+  expect(plan).toBeTruthy();
+});
+
+// ============================================================================
+// Cleanup
+// ============================================================================
+
+tap.test('queryplanner: cleanup', async () => {
+  await storage.close();
+  expect(true).toBeTrue();
+});
+
+export default tap.start();

test/test.tsmdb.session.ts

@@ -0,0 +1,361 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as smartmongo from '../ts/index.js';
+
+const { SessionEngine } = smartmongo.tsmdb;
+
+let sessionEngine: InstanceType<typeof SessionEngine>;
+
+// ============================================================================
+// Setup
+// ============================================================================
+
+tap.test('session: should create SessionEngine instance', async () => {
+  sessionEngine = new SessionEngine({
+    sessionTimeoutMs: 1000, // 1 second for testing
+    cleanupIntervalMs: 10000, // 10 seconds to avoid cleanup during tests
+  });
+  expect(sessionEngine).toBeTruthy();
+});
+
+// ============================================================================
+// Session Lifecycle Tests
+// ============================================================================
+
+tap.test('session: startSession should create session with auto-generated ID', async () => {
+  const session = sessionEngine.startSession();
+
+  expect(session).toBeTruthy();
+  expect(session.id).toBeTruthy();
+  expect(session.id.length).toBeGreaterThanOrEqual(32); // UUID hex string (32 or 36 with hyphens)
+  expect(session.createdAt).toBeGreaterThan(0);
+  expect(session.lastActivityAt).toBeGreaterThan(0);
+  expect(session.inTransaction).toBeFalse();
+});
+
+tap.test('session: startSession should create session with specified ID', async () => {
+  const customId = 'custom-session-id-12345';
+  const session = sessionEngine.startSession(customId);
+
+  expect(session.id).toEqual(customId);
+});
+
+tap.test('session: startSession should create session with metadata', async () => {
+  const metadata = { client: 'test-client', version: '1.0' };
+  const session = sessionEngine.startSession(undefined, metadata);
+
+  expect(session.metadata).toBeTruthy();
+  expect(session.metadata!.client).toEqual('test-client');
+  expect(session.metadata!.version).toEqual('1.0');
+});
+
+tap.test('session: getSession should return session by ID', async () => {
+  const created = sessionEngine.startSession('get-session-test');
+  const retrieved = sessionEngine.getSession('get-session-test');
+
+  expect(retrieved).toBeTruthy();
+  expect(retrieved!.id).toEqual('get-session-test');
+  expect(retrieved!.id).toEqual(created.id);
+});
+
+tap.test('session: getSession should return undefined for non-existent session', async () => {
+  const session = sessionEngine.getSession('non-existent-session-id');
+  expect(session).toBeUndefined();
+});
+
+tap.test('session: touchSession should update lastActivityAt', async () => {
+  const session = sessionEngine.startSession('touch-test-session');
+  const originalLastActivity = session.lastActivityAt;
+
+  // Wait a bit to ensure time difference
+  await new Promise(resolve => setTimeout(resolve, 10));
+
+  const touched = sessionEngine.touchSession('touch-test-session');
+  expect(touched).toBeTrue();
+
+  const updated = sessionEngine.getSession('touch-test-session');
+  expect(updated!.lastActivityAt).toBeGreaterThanOrEqual(originalLastActivity);
+});
+
+tap.test('session: touchSession should return false for non-existent session', async () => {
+  const touched = sessionEngine.touchSession('non-existent-touch-session');
+  expect(touched).toBeFalse();
+});
+
+tap.test('session: endSession should remove the session', async () => {
+  sessionEngine.startSession('end-session-test');
+  expect(sessionEngine.getSession('end-session-test')).toBeTruthy();
+
+  const ended = await sessionEngine.endSession('end-session-test');
+  expect(ended).toBeTrue();
+
+  expect(sessionEngine.getSession('end-session-test')).toBeUndefined();
+});
+
+tap.test('session: endSession should return false for non-existent session', async () => {
+  const ended = await sessionEngine.endSession('non-existent-end-session');
+  expect(ended).toBeFalse();
+});
+
+// ============================================================================
+// Session Expiry Tests
+// ============================================================================
+
+tap.test('session: isSessionExpired should return false for fresh session', async () => {
+  const session = sessionEngine.startSession('fresh-session');
+  const isExpired = sessionEngine.isSessionExpired(session);
+  expect(isExpired).toBeFalse();
+});
+
+tap.test('session: isSessionExpired should return true for old session', async () => {
+  // Create a session with old lastActivityAt
+  const session = sessionEngine.startSession('old-session');
+  // Manually set lastActivityAt to old value (sessionTimeoutMs is 1000ms)
+  (session as any).lastActivityAt = Date.now() - 2000;
+
+  const isExpired = sessionEngine.isSessionExpired(session);
+  expect(isExpired).toBeTrue();
+});
+
+tap.test('session: getSession should return undefined for expired session', async () => {
+  const session = sessionEngine.startSession('expiring-session');
+  // Manually expire the session
+  (session as any).lastActivityAt = Date.now() - 2000;
+
+  const retrieved = sessionEngine.getSession('expiring-session');
+  expect(retrieved).toBeUndefined();
+});
+
+// ============================================================================
+// Transaction Integration Tests
+// ============================================================================
+
+tap.test('session: startTransaction should mark session as in transaction', async () => {
+  sessionEngine.startSession('txn-session-1');
+  const started = sessionEngine.startTransaction('txn-session-1', 'txn-id-1', 1);
+
+  expect(started).toBeTrue();
+
+  const session = sessionEngine.getSession('txn-session-1');
+  expect(session!.inTransaction).toBeTrue();
+  expect(session!.txnId).toEqual('txn-id-1');
+  expect(session!.txnNumber).toEqual(1);
+});
+
+tap.test('session: startTransaction should return false for non-existent session', async () => {
+  const started = sessionEngine.startTransaction('non-existent-txn-session', 'txn-id');
+  expect(started).toBeFalse();
+});
+
+tap.test('session: endTransaction should clear transaction state', async () => {
+  sessionEngine.startSession('txn-session-2');
+  sessionEngine.startTransaction('txn-session-2', 'txn-id-2');
+
+  const ended = sessionEngine.endTransaction('txn-session-2');
+  expect(ended).toBeTrue();
+
+  const session = sessionEngine.getSession('txn-session-2');
+  expect(session!.inTransaction).toBeFalse();
+  expect(session!.txnId).toBeUndefined();
+  expect(session!.txnNumber).toBeUndefined();
+});
+
+tap.test('session: endTransaction should return false for non-existent session', async () => {
+  const ended = sessionEngine.endTransaction('non-existent-end-txn-session');
+  expect(ended).toBeFalse();
+});
+
+tap.test('session: getTransactionId should return transaction ID', async () => {
+  sessionEngine.startSession('txn-id-session');
+  sessionEngine.startTransaction('txn-id-session', 'my-txn-id');
+
+  const txnId = sessionEngine.getTransactionId('txn-id-session');
+  expect(txnId).toEqual('my-txn-id');
+});
+
+tap.test('session: getTransactionId should return undefined for session without transaction', async () => {
+  sessionEngine.startSession('no-txn-session');
+  const txnId = sessionEngine.getTransactionId('no-txn-session');
+  expect(txnId).toBeUndefined();
+});
+
+tap.test('session: getTransactionId should return undefined for non-existent session', async () => {
+  const txnId = sessionEngine.getTransactionId('non-existent-txn-id-session');
+  expect(txnId).toBeUndefined();
+});
+
+tap.test('session: isInTransaction should return correct state', async () => {
+  sessionEngine.startSession('in-txn-check-session');
+
+  expect(sessionEngine.isInTransaction('in-txn-check-session')).toBeFalse();
+
+  sessionEngine.startTransaction('in-txn-check-session', 'txn-check');
+  expect(sessionEngine.isInTransaction('in-txn-check-session')).toBeTrue();
+
+  sessionEngine.endTransaction('in-txn-check-session');
+  expect(sessionEngine.isInTransaction('in-txn-check-session')).toBeFalse();
+});
+
+tap.test('session: isInTransaction should return false for non-existent session', async () => {
+  expect(sessionEngine.isInTransaction('non-existent-in-txn-session')).toBeFalse();
+});
+
+// ============================================================================
+// Session Listing Tests
+// ============================================================================
+
+tap.test('session: listSessions should return all active sessions', async () => {
+  // Close and recreate to have a clean slate
+  sessionEngine.close();
+  sessionEngine = new SessionEngine({
+    sessionTimeoutMs: 10000,
+    cleanupIntervalMs: 60000,
+  });
+
+  sessionEngine.startSession('list-session-1');
+  sessionEngine.startSession('list-session-2');
+  sessionEngine.startSession('list-session-3');
+
+  const sessions = sessionEngine.listSessions();
+  expect(sessions.length).toEqual(3);
+});
+
+tap.test('session: listSessions should not include expired sessions', async () => {
+  const session = sessionEngine.startSession('expired-list-session');
+  // Expire the session
+  (session as any).lastActivityAt = Date.now() - 20000;
+
+  const sessions = sessionEngine.listSessions();
+  const found = sessions.find(s => s.id === 'expired-list-session');
+  expect(found).toBeUndefined();
+});
+
+tap.test('session: getSessionCount should return correct count', async () => {
+  const count = sessionEngine.getSessionCount();
+  expect(count).toBeGreaterThanOrEqual(3); // We created 3 sessions above
+});
+
+tap.test('session: getSessionsWithTransactions should filter correctly', async () => {
+  // Clean slate
+  sessionEngine.close();
+  sessionEngine = new SessionEngine({
+    sessionTimeoutMs: 10000,
+    cleanupIntervalMs: 60000,
+  });
+
+  sessionEngine.startSession('no-txn-1');
+  sessionEngine.startSession('no-txn-2');
+  sessionEngine.startSession('with-txn-1');
+  sessionEngine.startSession('with-txn-2');
+
+  sessionEngine.startTransaction('with-txn-1', 'txn-a');
+  sessionEngine.startTransaction('with-txn-2', 'txn-b');
+
+  const txnSessions = sessionEngine.getSessionsWithTransactions();
+  expect(txnSessions.length).toEqual(2);
+  expect(txnSessions.every(s => s.inTransaction)).toBeTrue();
+});
+
+// ============================================================================
+// getOrCreateSession Tests
+// ============================================================================
+
+tap.test('session: getOrCreateSession should create if missing', async () => {
+  const session = sessionEngine.getOrCreateSession('get-or-create-new');
+  expect(session).toBeTruthy();
+  expect(session.id).toEqual('get-or-create-new');
+});
+
+tap.test('session: getOrCreateSession should return existing session', async () => {
+  const created = sessionEngine.startSession('get-or-create-existing');
+  const retrieved = sessionEngine.getOrCreateSession('get-or-create-existing');
+
+  expect(retrieved.id).toEqual(created.id);
+  expect(retrieved.createdAt).toEqual(created.createdAt);
+});
+
+tap.test('session: getOrCreateSession should touch existing session', async () => {
+  const session = sessionEngine.startSession('get-or-create-touch');
+  const originalLastActivity = session.lastActivityAt;
+
+  await new Promise(resolve => setTimeout(resolve, 10));
+
+  sessionEngine.getOrCreateSession('get-or-create-touch');
+  const updated = sessionEngine.getSession('get-or-create-touch');
+
+  expect(updated!.lastActivityAt).toBeGreaterThanOrEqual(originalLastActivity);
+});
+
+// ============================================================================
+// extractSessionId Static Method Tests
+// ============================================================================
+
+tap.test('session: extractSessionId should handle UUID object', async () => {
+  const { ObjectId } = smartmongo.tsmdb;
+  const uuid = new smartmongo.tsmdb.plugins.bson.UUID();
+  const lsid = { id: uuid };
+
+  const extracted = SessionEngine.extractSessionId(lsid);
+  expect(extracted).toEqual(uuid.toHexString());
+});
+
+tap.test('session: extractSessionId should handle string ID', async () => {
+  const lsid = { id: 'string-session-id' };
+
+  const extracted = SessionEngine.extractSessionId(lsid);
+  expect(extracted).toEqual('string-session-id');
+});
+
+tap.test('session: extractSessionId should handle binary format', async () => {
+  const binaryData = Buffer.from('test-binary-uuid', 'utf8').toString('base64');
+  const lsid = { id: { $binary: { base64: binaryData } } };
+
+  const extracted = SessionEngine.extractSessionId(lsid);
+  expect(extracted).toBeTruthy();
+  expect(typeof extracted).toEqual('string');
+});
+
+tap.test('session: extractSessionId should return undefined for null/undefined', async () => {
+  expect(SessionEngine.extractSessionId(null)).toBeUndefined();
+  expect(SessionEngine.extractSessionId(undefined)).toBeUndefined();
+});
+
+tap.test('session: extractSessionId should return undefined for empty object', async () => {
+  expect(SessionEngine.extractSessionId({})).toBeUndefined();
+});
+
+// ============================================================================
+// refreshSession Tests
+// ============================================================================
+
+tap.test('session: refreshSession should update lastActivityAt', async () => {
+  const session = sessionEngine.startSession('refresh-session-test');
+  const originalLastActivity = session.lastActivityAt;
+
+  await new Promise(resolve => setTimeout(resolve, 10));
+
+  const refreshed = sessionEngine.refreshSession('refresh-session-test');
+  expect(refreshed).toBeTrue();
+
+  const updated = sessionEngine.getSession('refresh-session-test');
+  expect(updated!.lastActivityAt).toBeGreaterThanOrEqual(originalLastActivity);
+});
+
+tap.test('session: refreshSession should return false for non-existent session', async () => {
+  const refreshed = sessionEngine.refreshSession('non-existent-refresh-session');
+  expect(refreshed).toBeFalse();
+});
+
+// ============================================================================
+// Cleanup
+// ============================================================================
+
+tap.test('session: close should clear all sessions', async () => {
+  sessionEngine.startSession('close-test-session');
+  expect(sessionEngine.getSessionCount()).toBeGreaterThan(0);
+
+  sessionEngine.close();
+
+  expect(sessionEngine.getSessionCount()).toEqual(0);
+});
+
+export default tap.start();

test/test.tsmdb.ts

@@ -2,9 +2,9 @@ import { expect, tap } from '@git.zone/tstest/tapbundle';
 import * as smartmongo from '../ts/index.js';
 import { MongoClient, Db, Collection } from 'mongodb';
 
-const { congodb } = smartmongo;
+const { tsmdb } = smartmongo;
 
-let server: smartmongo.congodb.CongoServer;
+let server: smartmongo.tsmdb.TsmdbServer;
 let client: MongoClient;
 let db: Db;
 
@@ -12,13 +12,13 @@ let db: Db;
 // Server Startup
 // ============================================================================
 
-tap.test('congodb: should start the server', async () => {
-  server = new congodb.CongoServer({ port: 27117 }); // Use non-standard port for tests
+tap.test('tsmdb: should start the server', async () => {
+  server = new tsmdb.TsmdbServer({ port: 27117 }); // Use non-standard port for tests
   await server.start();
   expect(server.running).toBeTrue();
 });
 
-tap.test('congodb: should connect with official MongoClient', async () => {
+tap.test('tsmdb: should connect with official MongoClient', async () => {
   client = new MongoClient('mongodb://127.0.0.1:27117', {
     directConnection: true,
     serverSelectionTimeoutMS: 5000,
@@ -27,7 +27,7 @@ tap.test('congodb: should connect with official MongoClient', async () => {
   expect(client).toBeTruthy();
 });
 
-tap.test('congodb: should get a database instance', async () => {
+tap.test('tsmdb: should get a database instance', async () => {
   db = client.db('testdb');
   expect(db).toBeTruthy();
   expect(db.databaseName).toEqual('testdb');
@@ -37,7 +37,7 @@ tap.test('congodb: should get a database instance', async () => {
 // Basic CRUD Tests
 // ============================================================================
 
-tap.test('congodb: insertOne - should insert a document', async () => {
+tap.test('tsmdb: insertOne - should insert a document', async () => {
   const collection = db.collection('users');
   const result = await collection.insertOne({
     name: 'John Doe',
@@ -49,7 +49,7 @@ tap.test('congodb: insertOne - should insert a document', async () => {
   expect(result.insertedId).toBeTruthy();
 });
 
-tap.test('congodb: insertMany - should insert multiple documents', async () => {
+tap.test('tsmdb: insertMany - should insert multiple documents', async () => {
   const collection = db.collection('users');
   const result = await collection.insertMany([
     { name: 'Jane Doe', email: 'jane@example.com', age: 25 },
@@ -62,7 +62,7 @@ tap.test('congodb: insertMany - should insert multiple documents', async () => {
   expect(Object.keys(result.insertedIds).length).toEqual(3);
 });
 
-tap.test('congodb: findOne - should find a single document', async () => {
+tap.test('tsmdb: findOne - should find a single document', async () => {
   const collection = db.collection('users');
   const doc = await collection.findOne({ name: 'John Doe' });
 
@@ -71,14 +71,14 @@ tap.test('congodb: findOne - should find a single document', async () => {
   expect(doc!.email).toEqual('john@example.com');
 });
 
-tap.test('congodb: find - should find multiple documents', async () => {
+tap.test('tsmdb: find - should find multiple documents', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({ age: { $gte: 28 } }).toArray();
 
   expect(docs.length).toEqual(3);
 });
 
-tap.test('congodb: updateOne - should update a single document', async () => {
+tap.test('tsmdb: updateOne - should update a single document', async () => {
   const collection = db.collection('users');
   const result = await collection.updateOne(
     { name: 'John Doe' },
@@ -93,7 +93,7 @@ tap.test('congodb: updateOne - should update a single document', async () => {
   expect(updated!.age).toEqual(31);
 });
 
-tap.test('congodb: updateMany - should update multiple documents', async () => {
+tap.test('tsmdb: updateMany - should update multiple documents', async () => {
   const collection = db.collection('users');
   const result = await collection.updateMany(
     { age: { $gte: 30 } },
@@ -105,7 +105,7 @@ tap.test('congodb: updateMany - should update multiple documents', async () => {
   expect(result.modifiedCount).toEqual(2);
 });
 
-tap.test('congodb: deleteOne - should delete a single document', async () => {
+tap.test('tsmdb: deleteOne - should delete a single document', async () => {
   const collection = db.collection('users');
   const result = await collection.deleteOne({ name: 'Bob Smith' });
 
@@ -113,7 +113,7 @@ tap.test('congodb: deleteOne - should delete a single document', async () => {
   expect(result.deletedCount).toEqual(1);
 });
 
-tap.test('congodb: deleteMany - should delete multiple documents', async () => {
+tap.test('tsmdb: deleteMany - should delete multiple documents', async () => {
   const collection = db.collection('users');
 
   // First add some test docs to delete
@@ -132,32 +132,32 @@ tap.test('congodb: deleteMany - should delete multiple documents', async () => {
 // Query Operator Tests
 // ============================================================================
 
-tap.test('congodb: query - $eq operator', async () => {
+tap.test('tsmdb: query - $eq operator', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({ name: { $eq: 'Jane Doe' } }).toArray();
   expect(docs.length).toEqual(1);
   expect(docs[0].name).toEqual('Jane Doe');
 });
 
-tap.test('congodb: query - $ne operator', async () => {
+tap.test('tsmdb: query - $ne operator', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({ name: { $ne: 'Jane Doe' } }).toArray();
   expect(docs.every(d => d.name !== 'Jane Doe')).toBeTrue();
 });
 
-tap.test('congodb: query - $gt and $lt operators', async () => {
+tap.test('tsmdb: query - $gt and $lt operators', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({ age: { $gt: 25, $lt: 35 } }).toArray();
   expect(docs.every(d => d.age > 25 && d.age < 35)).toBeTrue();
 });
 
-tap.test('congodb: query - $in operator', async () => {
+tap.test('tsmdb: query - $in operator', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({ name: { $in: ['Jane Doe', 'Alice Johnson'] } }).toArray();
   expect(docs.length).toEqual(2);
 });
 
-tap.test('congodb: query - $or operator', async () => {
+tap.test('tsmdb: query - $or operator', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({
     $or: [
@@ -168,7 +168,7 @@ tap.test('congodb: query - $or operator', async () => {
   expect(docs.length).toBeGreaterThanOrEqual(1);
 });
 
-tap.test('congodb: query - $and operator', async () => {
+tap.test('tsmdb: query - $and operator', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({
     $and: [
@@ -179,7 +179,7 @@ tap.test('congodb: query - $and operator', async () => {
   expect(docs.every(d => d.age >= 25 && d.age <= 30)).toBeTrue();
 });
 
-tap.test('congodb: query - $exists operator', async () => {
+tap.test('tsmdb: query - $exists operator', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({ senior: { $exists: true } }).toArray();
   expect(docs.every(d => 'senior' in d)).toBeTrue();
@@ -189,7 +189,7 @@ tap.test('congodb: query - $exists operator', async () => {
 // Update Operator Tests
 // ============================================================================
 
-tap.test('congodb: update - $inc operator', async () => {
+tap.test('tsmdb: update - $inc operator', async () => {
   const collection = db.collection('users');
   await collection.updateOne(
     { name: 'Jane Doe' },
@@ -200,7 +200,7 @@ tap.test('congodb: update - $inc operator', async () => {
   expect(updated!.age).toEqual(26);
 });
 
-tap.test('congodb: update - $unset operator', async () => {
+tap.test('tsmdb: update - $unset operator', async () => {
   const collection = db.collection('users');
   await collection.updateOne(
     { name: 'Jane Doe' },
@@ -211,7 +211,7 @@ tap.test('congodb: update - $unset operator', async () => {
   expect('senior' in updated!).toBeFalse();
 });
 
-tap.test('congodb: update - $push operator', async () => {
+tap.test('tsmdb: update - $push operator', async () => {
   const collection = db.collection('users');
   await collection.updateOne(
     { name: 'Jane Doe' },
@@ -227,7 +227,7 @@ tap.test('congodb: update - $push operator', async () => {
   expect(updated!.tags).toContain('tester');
 });
 
-tap.test('congodb: update - $pull operator', async () => {
+tap.test('tsmdb: update - $pull operator', async () => {
   const collection = db.collection('users');
   await collection.updateOne(
     { name: 'Jane Doe' },
@@ -238,7 +238,7 @@ tap.test('congodb: update - $pull operator', async () => {
   expect(updated!.tags).not.toContain('tester');
 });
 
-tap.test('congodb: update - upsert creates new document', async () => {
+tap.test('tsmdb: update - upsert creates new document', async () => {
   const collection = db.collection('users');
   const result = await collection.updateOne(
     { name: 'New User' },
@@ -258,7 +258,7 @@ tap.test('congodb: update - upsert creates new document', async () => {
 // Cursor Tests
 // ============================================================================
 
-tap.test('congodb: cursor - sort', async () => {
+tap.test('tsmdb: cursor - sort', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({}).sort({ age: -1 }).toArray();
 
@@ -269,13 +269,13 @@ tap.test('congodb: cursor - sort', async () => {
   }
 });
 
-tap.test('congodb: cursor - limit', async () => {
+tap.test('tsmdb: cursor - limit', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({}).limit(2).toArray();
   expect(docs.length).toBeLessThanOrEqual(2);
 });
 
-tap.test('congodb: cursor - skip', async () => {
+tap.test('tsmdb: cursor - skip', async () => {
   const collection = db.collection('users');
   const allDocs = await collection.find({}).toArray();
   const skippedDocs = await collection.find({}).skip(1).toArray();
@@ -283,7 +283,7 @@ tap.test('congodb: cursor - skip', async () => {
   expect(skippedDocs.length).toEqual(Math.max(0, allDocs.length - 1));
 });
 
-tap.test('congodb: cursor - project', async () => {
+tap.test('tsmdb: cursor - project', async () => {
   const collection = db.collection('users');
   const docs = await collection.find({}).project({ name: 1, _id: 0 }).toArray();
 
@@ -296,7 +296,7 @@ tap.test('congodb: cursor - project', async () => {
 // FindOneAnd* Tests
 // ============================================================================
 
-tap.test('congodb: findOneAndUpdate - returns updated document', async () => {
+tap.test('tsmdb: findOneAndUpdate - returns updated document', async () => {
   const collection = db.collection('users');
   const result = await collection.findOneAndUpdate(
     { name: 'Jane Doe' },
@@ -308,7 +308,7 @@ tap.test('congodb: findOneAndUpdate - returns updated document', async () => {
   expect(result!.status).toEqual('active');
 });
 
-tap.test('congodb: findOneAndDelete - returns deleted document', async () => {
+tap.test('tsmdb: findOneAndDelete - returns deleted document', async () => {
   const collection = db.collection('users');
 
   // Insert a temp doc to delete
@@ -328,19 +328,19 @@ tap.test('congodb: findOneAndDelete - returns deleted document', async () => {
 // Count and Distinct Tests
 // ============================================================================
 
-tap.test('congodb: countDocuments - counts matching documents', async () => {
+tap.test('tsmdb: countDocuments - counts matching documents', async () => {
   const collection = db.collection('users');
   const count = await collection.countDocuments({ age: { $gte: 25 } });
   expect(count).toBeGreaterThan(0);
 });
 
-tap.test('congodb: estimatedDocumentCount - returns total count', async () => {
+tap.test('tsmdb: estimatedDocumentCount - returns total count', async () => {
   const collection = db.collection('users');
   const count = await collection.estimatedDocumentCount();
   expect(count).toBeGreaterThan(0);
 });
 
-tap.test('congodb: distinct - returns unique values', async () => {
+tap.test('tsmdb: distinct - returns unique values', async () => {
   const collection = db.collection('users');
   const names = await collection.distinct('name');
 
@@ -353,7 +353,7 @@ tap.test('congodb: distinct - returns unique values', async () => {
 // Index Tests
 // ============================================================================
 
-tap.test('congodb: createIndex - creates a single index', async () => {
+tap.test('tsmdb: createIndex - creates a single index', async () => {
   const collection = db.collection('users');
   const indexName = await collection.createIndex({ email: 1 });
 
@@ -361,14 +361,14 @@ tap.test('congodb: createIndex - creates a single index', async () => {
   expect(indexName).toContain('email');
 });
 
-tap.test('congodb: createIndex - creates compound index', async () => {
+tap.test('tsmdb: createIndex - creates compound index', async () => {
   const collection = db.collection('users');
   const indexName = await collection.createIndex({ name: 1, age: -1 });
 
   expect(indexName).toBeTruthy();
 });
 
-tap.test('congodb: listIndexes - lists all indexes', async () => {
+tap.test('tsmdb: listIndexes - lists all indexes', async () => {
   const collection = db.collection('users');
   const indexes = await collection.listIndexes().toArray();
 
@@ -376,7 +376,7 @@ tap.test('congodb: listIndexes - lists all indexes', async () => {
   expect(indexes.some(i => i.name === '_id_')).toBeTrue();
 });
 
-tap.test('congodb: dropIndex - drops an index', async () => {
+tap.test('tsmdb: dropIndex - drops an index', async () => {
   const collection = db.collection('users');
   const indexName = await collection.createIndex({ toDropField: 1 });
 
@@ -390,7 +390,7 @@ tap.test('congodb: dropIndex - drops an index', async () => {
 // Aggregation Tests
 // ============================================================================
 
-tap.test('congodb: aggregate - $match stage', async () => {
+tap.test('tsmdb: aggregate - $match stage', async () => {
   const collection = db.collection('users');
   const results = await collection.aggregate([
     { $match: { age: { $gte: 25 } } }
@@ -400,7 +400,7 @@ tap.test('congodb: aggregate - $match stage', async () => {
   expect(results.every(d => d.age >= 25)).toBeTrue();
 });
 
-tap.test('congodb: aggregate - $project stage', async () => {
+tap.test('tsmdb: aggregate - $project stage', async () => {
   const collection = db.collection('users');
   const results = await collection.aggregate([
     { $project: { name: 1, _id: 0 } }
@@ -411,7 +411,7 @@ tap.test('congodb: aggregate - $project stage', async () => {
   expect(results[0].email).toBeUndefined();
 });
 
-tap.test('congodb: aggregate - $sort stage', async () => {
+tap.test('tsmdb: aggregate - $sort stage', async () => {
   const collection = db.collection('users');
   const results = await collection.aggregate([
     { $match: { age: { $exists: true } } },
@@ -423,7 +423,7 @@ tap.test('congodb: aggregate - $sort stage', async () => {
   }
 });
 
-tap.test('congodb: aggregate - $group stage', async () => {
+tap.test('tsmdb: aggregate - $group stage', async () => {
   const collection = db.collection('users');
 
   // Add some categorized data
@@ -445,7 +445,7 @@ tap.test('congodb: aggregate - $group stage', async () => {
   expect(groupB!.total).toEqual(30);
 });
 
-tap.test('congodb: aggregate - $limit and $skip stages', async () => {
+tap.test('tsmdb: aggregate - $limit and $skip stages', async () => {
   const collection = db.collection('users');
   const results = await collection.aggregate([
     { $skip: 1 },
@@ -459,7 +459,7 @@ tap.test('congodb: aggregate - $limit and $skip stages', async () => {
 // Bulk Operations Tests
 // ============================================================================
 
-tap.test('congodb: bulkWrite - executes multiple operations', async () => {
+tap.test('tsmdb: bulkWrite - executes multiple operations', async () => {
   const collection = db.collection('bulktest');
 
   const result = await collection.bulkWrite([
@@ -476,18 +476,18 @@ tap.test('congodb: bulkWrite - executes multiple operations', async () => {
 // Database Operations Tests
 // ============================================================================
 
-tap.test('congodb: listCollections - lists all collections', async () => {
+tap.test('tsmdb: listCollections - lists all collections', async () => {
   const collections = await db.listCollections().toArray();
   expect(collections.length).toBeGreaterThan(0);
 });
 
-tap.test('congodb: createCollection - creates a new collection', async () => {
+tap.test('tsmdb: createCollection - creates a new collection', async () => {
   await db.createCollection('newcollection');
   const collections = await db.listCollections().toArray();
   expect(collections.some(c => c.name === 'newcollection')).toBeTrue();
 });
 
-tap.test('congodb: dropCollection - drops a collection', async () => {
+tap.test('tsmdb: dropCollection - drops a collection', async () => {
   await db.createCollection('todrop');
   await db.dropCollection('todrop');
   const collections = await db.listCollections().toArray();
@@ -498,20 +498,20 @@ tap.test('congodb: dropCollection - drops a collection', async () => {
 // Admin Tests
 // ============================================================================
 
-tap.test('congodb: admin - listDatabases', async () => {
+tap.test('tsmdb: admin - listDatabases', async () => {
   const admin = client.db().admin();
   const result = await admin.listDatabases();
   expect(result.ok).toEqual(1);
   expect(result.databases).toBeArray();
 });
 
-tap.test('congodb: admin - serverStatus', async () => {
+tap.test('tsmdb: admin - serverStatus', async () => {
   const admin = client.db().admin();
   const status = await admin.serverStatus();
   expect(status.ok).toEqual(1);
 });
 
-tap.test('congodb: admin - ping', async () => {
+tap.test('tsmdb: admin - ping', async () => {
   const admin = client.db().admin();
   const result = await admin.ping();
   expect(result.ok).toEqual(1);
@@ -521,7 +521,7 @@ tap.test('congodb: admin - ping', async () => {
 // Replace Operations Tests
 // ============================================================================
 
-tap.test('congodb: replaceOne - replaces entire document', async () => {
+tap.test('tsmdb: replaceOne - replaces entire document', async () => {
   const collection = db.collection('replacetest');
   await collection.insertOne({ name: 'Original', field1: 'value1', field2: 'value2' });
 
@@ -540,7 +540,7 @@ tap.test('congodb: replaceOne - replaces entire document', async () => {
   expect(replaced!.field2).toBeUndefined();
 });
 
-tap.test('congodb: findOneAndReplace - returns replaced document', async () => {
+tap.test('tsmdb: findOneAndReplace - returns replaced document', async () => {
   const collection = db.collection('replacetest');
   await collection.insertOne({ name: 'ToReplace', data: 'old' });
 
@@ -558,12 +558,12 @@ tap.test('congodb: findOneAndReplace - returns replaced document', async () => {
 // Cleanup
 // ============================================================================
 
-tap.test('congodb: cleanup - drop database', async () => {
+tap.test('tsmdb: cleanup - drop database', async () => {
   const result = await db.dropDatabase();
   expect(result).toBeTrue();
 });
 
-tap.test('congodb: cleanup - close client and server', async () => {
+tap.test('tsmdb: cleanup - close client and server', async () => {
   await client.close();
   await server.stop();
   expect(server.running).toBeFalse();

test/test.tsmdb.wal.ts

@@ -0,0 +1,411 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+import * as smartmongo from '../ts/index.js';
+import * as path from 'path';
+import * as fs from 'fs/promises';
+
+const { WAL, ObjectId } = smartmongo.tsmdb;
+
+let wal: InstanceType<typeof WAL>;
+const TEST_WAL_PATH = '/tmp/tsmdb-test-wal/test.wal';
+
+// Helper to clean up test files
+async function cleanupTestFiles() {
+  try {
+    await fs.rm('/tmp/tsmdb-test-wal', { recursive: true, force: true });
+  } catch {
+    // Ignore if doesn't exist
+  }
+}
+
+// ============================================================================
+// Setup
+// ============================================================================
+
+tap.test('wal: cleanup before tests', async () => {
+  await cleanupTestFiles();
+});
+
+tap.test('wal: should create WAL instance', async () => {
+  wal = new WAL(TEST_WAL_PATH, { checkpointInterval: 100 });
+  expect(wal).toBeTruthy();
+});
+
+tap.test('wal: should initialize WAL', async () => {
+  const result = await wal.initialize();
+  expect(result).toBeTruthy();
+  expect(result.recoveredEntries).toBeArray();
+  expect(result.recoveredEntries.length).toEqual(0);
+});
+
+// ============================================================================
+// LSN Tests
+// ============================================================================
+
+tap.test('wal: getCurrentLsn should return 0 initially', async () => {
+  const lsn = wal.getCurrentLsn();
+  expect(lsn).toEqual(0);
+});
+
+tap.test('wal: LSN should increment after logging', async () => {
+  const doc = { _id: new ObjectId(), name: 'Test' };
+  const lsn = await wal.logInsert('testdb', 'testcoll', doc as any);
+
+  expect(lsn).toEqual(1);
+  expect(wal.getCurrentLsn()).toEqual(1);
+});
+
+// ============================================================================
+// Insert Logging Tests
+// ============================================================================
+
+tap.test('wal: logInsert should create entry with correct structure', async () => {
+  const doc = { _id: new ObjectId(), name: 'InsertTest', value: 42 };
+  const lsn = await wal.logInsert('testdb', 'insertcoll', doc as any);
+
+  expect(lsn).toBeGreaterThan(0);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  expect(entry).toBeTruthy();
+  expect(entry!.operation).toEqual('insert');
+  expect(entry!.dbName).toEqual('testdb');
+  expect(entry!.collName).toEqual('insertcoll');
+  expect(entry!.documentId).toEqual(doc._id.toHexString());
+  expect(entry!.data).toBeTruthy();
+  expect(entry!.timestamp).toBeGreaterThan(0);
+  expect(entry!.checksum).toBeGreaterThan(0);
+});
+
+tap.test('wal: logInsert with transaction ID', async () => {
+  const doc = { _id: new ObjectId(), name: 'TxnInsertTest' };
+  const lsn = await wal.logInsert('testdb', 'insertcoll', doc as any, 'txn-123');
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  expect(entry!.txnId).toEqual('txn-123');
+});
+
+// ============================================================================
+// Update Logging Tests
+// ============================================================================
+
+tap.test('wal: logUpdate should store old and new document', async () => {
+  const oldDoc = { _id: new ObjectId(), name: 'OldName', value: 1 };
+  const newDoc = { ...oldDoc, name: 'NewName', value: 2 };
+
+  const lsn = await wal.logUpdate('testdb', 'updatecoll', oldDoc as any, newDoc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  expect(entry).toBeTruthy();
+  expect(entry!.operation).toEqual('update');
+  expect(entry!.data).toBeTruthy();
+  expect(entry!.previousData).toBeTruthy();
+  expect(entry!.documentId).toEqual(oldDoc._id.toHexString());
+});
+
+// ============================================================================
+// Delete Logging Tests
+// ============================================================================
+
+tap.test('wal: logDelete should record deleted document', async () => {
+  const doc = { _id: new ObjectId(), name: 'ToDelete' };
+
+  const lsn = await wal.logDelete('testdb', 'deletecoll', doc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  expect(entry).toBeTruthy();
+  expect(entry!.operation).toEqual('delete');
+  expect(entry!.previousData).toBeTruthy();
+  expect(entry!.data).toBeUndefined();
+});
+
+// ============================================================================
+// Transaction Logging Tests
+// ============================================================================
+
+tap.test('wal: logBeginTransaction should create begin entry', async () => {
+  const lsn = await wal.logBeginTransaction('txn-begin-test');
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  expect(entry).toBeTruthy();
+  expect(entry!.operation).toEqual('begin');
+  expect(entry!.txnId).toEqual('txn-begin-test');
+});
+
+tap.test('wal: logCommitTransaction should create commit entry', async () => {
+  const lsn = await wal.logCommitTransaction('txn-commit-test');
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  expect(entry).toBeTruthy();
+  expect(entry!.operation).toEqual('commit');
+  expect(entry!.txnId).toEqual('txn-commit-test');
+});
+
+tap.test('wal: logAbortTransaction should create abort entry', async () => {
+  const lsn = await wal.logAbortTransaction('txn-abort-test');
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  expect(entry).toBeTruthy();
+  expect(entry!.operation).toEqual('abort');
+  expect(entry!.txnId).toEqual('txn-abort-test');
+});
+
+// ============================================================================
+// getTransactionEntries Tests
+// ============================================================================
+
+tap.test('wal: getTransactionEntries should return entries for transaction', async () => {
+  // Log a complete transaction
+  const txnId = 'txn-entries-test';
+  await wal.logBeginTransaction(txnId);
+
+  const doc1 = { _id: new ObjectId(), name: 'TxnDoc1' };
+  await wal.logInsert('testdb', 'txncoll', doc1 as any, txnId);
+
+  const doc2 = { _id: new ObjectId(), name: 'TxnDoc2' };
+  await wal.logInsert('testdb', 'txncoll', doc2 as any, txnId);
+
+  await wal.logCommitTransaction(txnId);
+
+  const entries = wal.getTransactionEntries(txnId);
+
+  expect(entries.length).toEqual(4); // begin + 2 inserts + commit
+  expect(entries.every(e => e.txnId === txnId)).toBeTrue();
+});
+
+tap.test('wal: getTransactionEntries should return empty for unknown transaction', async () => {
+  const entries = wal.getTransactionEntries('unknown-txn-id');
+  expect(entries.length).toEqual(0);
+});
+
+// ============================================================================
+// getEntriesAfter Tests
+// ============================================================================
+
+tap.test('wal: getEntriesAfter should filter by LSN', async () => {
+  const currentLsn = wal.getCurrentLsn();
+
+  // Add more entries
+  const doc = { _id: new ObjectId(), name: 'AfterTest' };
+  await wal.logInsert('testdb', 'aftercoll', doc as any);
+
+  const entries = wal.getEntriesAfter(currentLsn);
+  expect(entries.length).toEqual(1);
+  expect(entries[0].lsn).toBeGreaterThan(currentLsn);
+});
+
+tap.test('wal: getEntriesAfter with LSN 0 should return all entries', async () => {
+  const entries = wal.getEntriesAfter(0);
+  expect(entries.length).toBeGreaterThan(0);
+  expect(entries.length).toEqual(wal.getCurrentLsn());
+});
+
+// ============================================================================
+// Checkpoint Tests
+// ============================================================================
+
+tap.test('wal: checkpoint should create checkpoint entry', async () => {
+  const lsn = await wal.checkpoint();
+
+  expect(lsn).toBeGreaterThan(0);
+
+  // After checkpoint, getEntriesAfter(checkpoint) should be limited
+  const entries = wal.getEntriesAfter(0);
+  expect(entries.some(e => e.operation === 'checkpoint')).toBeTrue();
+});
+
+// ============================================================================
+// Document Recovery Tests
+// ============================================================================
+
+tap.test('wal: recoverDocument should deserialize document from entry', async () => {
+  const originalDoc = { _id: new ObjectId(), name: 'RecoverTest', nested: { a: 1, b: 2 } };
+  const lsn = await wal.logInsert('testdb', 'recovercoll', originalDoc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  const recovered = wal.recoverDocument(entry!);
+
+  expect(recovered).toBeTruthy();
+  expect(recovered!.name).toEqual('RecoverTest');
+  expect(recovered!.nested.a).toEqual(1);
+  expect(recovered!.nested.b).toEqual(2);
+});
+
+tap.test('wal: recoverDocument should return null for entry without data', async () => {
+  const lsn = await wal.logBeginTransaction('recover-no-data');
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  const recovered = wal.recoverDocument(entry!);
+  expect(recovered).toBeNull();
+});
+
+tap.test('wal: recoverPreviousDocument should deserialize previous state', async () => {
+  const oldDoc = { _id: new ObjectId(), name: 'Old', value: 100 };
+  const newDoc = { ...oldDoc, name: 'New', value: 200 };
+
+  const lsn = await wal.logUpdate('testdb', 'recovercoll', oldDoc as any, newDoc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  const previous = wal.recoverPreviousDocument(entry!);
+
+  expect(previous).toBeTruthy();
+  expect(previous!.name).toEqual('Old');
+  expect(previous!.value).toEqual(100);
+});
+
+tap.test('wal: recoverPreviousDocument should return null for insert entry', async () => {
+  const doc = { _id: new ObjectId(), name: 'NoPrevious' };
+  const lsn = await wal.logInsert('testdb', 'recovercoll', doc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  const previous = wal.recoverPreviousDocument(entry!);
+  expect(previous).toBeNull();
+});
+
+// ============================================================================
+// WAL Persistence and Recovery Tests
+// ============================================================================
+
+tap.test('wal: should persist and recover entries', async () => {
+  // Close current WAL
+  await wal.close();
+
+  // Create new WAL instance and initialize (should recover)
+  const wal2 = new WAL(TEST_WAL_PATH, { checkpointInterval: 100 });
+  const result = await wal2.initialize();
+
+  // Should have recovered entries
+  expect(result.recoveredEntries).toBeArray();
+  // After checkpoint, there might not be many recoverable entries
+  // but getCurrentLsn should be preserved or reset
+
+  await wal2.close();
+});
+
+// ============================================================================
+// Entry Checksum Tests
+// ============================================================================
+
+tap.test('wal: entries should have valid checksums', async () => {
+  wal = new WAL(TEST_WAL_PATH + '.checksum', { checkpointInterval: 100 });
+  await wal.initialize();
+
+  const doc = { _id: new ObjectId(), name: 'ChecksumTest' };
+  const lsn = await wal.logInsert('testdb', 'checksumcoll', doc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  expect(entry!.checksum).toBeGreaterThan(0);
+  expect(typeof entry!.checksum).toEqual('number');
+});
+
+// ============================================================================
+// Edge Cases
+// ============================================================================
+
+tap.test('wal: should handle special characters in document', async () => {
+  const doc = {
+    _id: new ObjectId(),
+    name: 'Test\nWith\tSpecial\r\nChars',
+    emoji: '🎉',
+    unicode: '日本語',
+  };
+
+  const lsn = await wal.logInsert('testdb', 'specialcoll', doc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  const recovered = wal.recoverDocument(entry!);
+  expect(recovered!.name).toEqual('Test\nWith\tSpecial\r\nChars');
+  expect(recovered!.emoji).toEqual('🎉');
+  expect(recovered!.unicode).toEqual('日本語');
+});
+
+tap.test('wal: should handle binary data in documents', async () => {
+  const doc = {
+    _id: new ObjectId(),
+    binaryField: Buffer.from([0x00, 0xFF, 0x7F, 0x80]),
+  };
+
+  const lsn = await wal.logInsert('testdb', 'binarycoll', doc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  const recovered = wal.recoverDocument(entry!);
+  expect(recovered).toBeTruthy();
+});
+
+tap.test('wal: should handle nested documents', async () => {
+  const doc = {
+    _id: new ObjectId(),
+    level1: {
+      level2: {
+        level3: {
+          value: 'deep',
+        },
+      },
+    },
+  };
+
+  const lsn = await wal.logInsert('testdb', 'nestedcoll', doc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  const recovered = wal.recoverDocument(entry!);
+  expect(recovered!.level1.level2.level3.value).toEqual('deep');
+});
+
+tap.test('wal: should handle arrays in documents', async () => {
+  const doc = {
+    _id: new ObjectId(),
+    tags: ['a', 'b', 'c'],
+    numbers: [1, 2, 3],
+    mixed: [1, 'two', { three: 3 }],
+  };
+
+  const lsn = await wal.logInsert('testdb', 'arraycoll', doc as any);
+
+  const entries = wal.getEntriesAfter(lsn - 1);
+  const entry = entries.find(e => e.lsn === lsn);
+
+  const recovered = wal.recoverDocument(entry!);
+  expect(recovered!.tags).toEqual(['a', 'b', 'c']);
+  expect(recovered!.numbers).toEqual([1, 2, 3]);
+  expect(recovered!.mixed[2].three).toEqual(3);
+});
+
+// ============================================================================
+// Cleanup
+// ============================================================================
+
+tap.test('wal: cleanup', async () => {
+  await wal.close();
+  await cleanupTestFiles();
+  expect(true).toBeTrue();
+});
+
+export default tap.start();

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartmongo',
-  version: '2.1.0',
+  version: '4.3.0',
   description: 'A module for creating and managing a local MongoDB instance for testing purposes.'
 }

ts/congodb/engine/IndexEngine.ts

@@ -1,479 +0,0 @@
-import * as plugins from '../congodb.plugins.js';
-import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
-import type {
-  Document,
-  IStoredDocument,
-  IIndexSpecification,
-  IIndexInfo,
-  ICreateIndexOptions,
-} from '../types/interfaces.js';
-import { CongoDuplicateKeyError, CongoIndexError } from '../errors/CongoErrors.js';
-import { QueryEngine } from './QueryEngine.js';
-
-/**
- * Index data structure for fast lookups
- */
-interface IIndexData {
-  name: string;
-  key: Record<string, 1 | -1 | string>;
-  unique: boolean;
-  sparse: boolean;
-  expireAfterSeconds?: number;
-  // Map from index key value to document _id(s)
-  entries: Map<string, Set<string>>;
-}
-
-/**
- * Index engine for managing indexes and query optimization
- */
-export class IndexEngine {
-  private dbName: string;
-  private collName: string;
-  private storage: IStorageAdapter;
-  private indexes: Map<string, IIndexData> = new Map();
-  private initialized = false;
-
-  constructor(dbName: string, collName: string, storage: IStorageAdapter) {
-    this.dbName = dbName;
-    this.collName = collName;
-    this.storage = storage;
-  }
-
-  /**
-   * Initialize indexes from storage
-   */
-  async initialize(): Promise<void> {
-    if (this.initialized) return;
-
-    const storedIndexes = await this.storage.getIndexes(this.dbName, this.collName);
-    const documents = await this.storage.findAll(this.dbName, this.collName);
-
-    for (const indexSpec of storedIndexes) {
-      const indexData: IIndexData = {
-        name: indexSpec.name,
-        key: indexSpec.key,
-        unique: indexSpec.unique || false,
-        sparse: indexSpec.sparse || false,
-        expireAfterSeconds: indexSpec.expireAfterSeconds,
-        entries: new Map(),
-      };
-
-      // Build index entries
-      for (const doc of documents) {
-        const keyValue = this.extractKeyValue(doc, indexSpec.key);
-        if (keyValue !== null || !indexData.sparse) {
-          const keyStr = JSON.stringify(keyValue);
-          if (!indexData.entries.has(keyStr)) {
-            indexData.entries.set(keyStr, new Set());
-          }
-          indexData.entries.get(keyStr)!.add(doc._id.toHexString());
-        }
-      }
-
-      this.indexes.set(indexSpec.name, indexData);
-    }
-
-    this.initialized = true;
-  }
-
-  /**
-   * Create a new index
-   */
-  async createIndex(
-    key: Record<string, 1 | -1 | 'text' | '2dsphere'>,
-    options?: ICreateIndexOptions
-  ): Promise<string> {
-    await this.initialize();
-
-    // Generate index name if not provided
-    const name = options?.name || this.generateIndexName(key);
-
-    // Check if index already exists
-    if (this.indexes.has(name)) {
-      return name;
-    }
-
-    // Create index data structure
-    const indexData: IIndexData = {
-      name,
-      key: key as Record<string, 1 | -1 | string>,
-      unique: options?.unique || false,
-      sparse: options?.sparse || false,
-      expireAfterSeconds: options?.expireAfterSeconds,
-      entries: new Map(),
-    };
-
-    // Build index from existing documents
-    const documents = await this.storage.findAll(this.dbName, this.collName);
-
-    for (const doc of documents) {
-      const keyValue = this.extractKeyValue(doc, key);
-
-      if (keyValue === null && indexData.sparse) {
-        continue;
-      }
-
-      const keyStr = JSON.stringify(keyValue);
-
-      if (indexData.unique && indexData.entries.has(keyStr)) {
-        throw new CongoDuplicateKeyError(
-          `E11000 duplicate key error index: ${this.dbName}.${this.collName}.$${name}`,
-          key as Record<string, 1>,
-          keyValue
-        );
-      }
-
-      if (!indexData.entries.has(keyStr)) {
-        indexData.entries.set(keyStr, new Set());
-      }
-      indexData.entries.get(keyStr)!.add(doc._id.toHexString());
-    }
-
-    // Store index
-    this.indexes.set(name, indexData);
-    await this.storage.saveIndex(this.dbName, this.collName, name, {
-      key,
-      unique: options?.unique,
-      sparse: options?.sparse,
-      expireAfterSeconds: options?.expireAfterSeconds,
-    });
-
-    return name;
-  }
-
-  /**
-   * Drop an index
-   */
-  async dropIndex(name: string): Promise<void> {
-    await this.initialize();
-
-    if (name === '_id_') {
-      throw new CongoIndexError('cannot drop _id index');
-    }
-
-    if (!this.indexes.has(name)) {
-      throw new CongoIndexError(`index not found: ${name}`);
-    }
-
-    this.indexes.delete(name);
-    await this.storage.dropIndex(this.dbName, this.collName, name);
-  }
-
-  /**
-   * Drop all indexes except _id
-   */
-  async dropAllIndexes(): Promise<void> {
-    await this.initialize();
-
-    const names = Array.from(this.indexes.keys()).filter(n => n !== '_id_');
-    for (const name of names) {
-      this.indexes.delete(name);
-      await this.storage.dropIndex(this.dbName, this.collName, name);
-    }
-  }
-
-  /**
-   * List all indexes
-   */
-  async listIndexes(): Promise<IIndexInfo[]> {
-    await this.initialize();
-
-    return Array.from(this.indexes.values()).map(idx => ({
-      v: 2,
-      key: idx.key,
-      name: idx.name,
-      unique: idx.unique || undefined,
-      sparse: idx.sparse || undefined,
-      expireAfterSeconds: idx.expireAfterSeconds,
-    }));
-  }
-
-  /**
-   * Check if an index exists
-   */
-  async indexExists(name: string): Promise<boolean> {
-    await this.initialize();
-    return this.indexes.has(name);
-  }
-
-  /**
-   * Update index entries after document insert
-   */
-  async onInsert(doc: IStoredDocument): Promise<void> {
-    await this.initialize();
-
-    for (const [name, indexData] of this.indexes) {
-      const keyValue = this.extractKeyValue(doc, indexData.key);
-
-      if (keyValue === null && indexData.sparse) {
-        continue;
-      }
-
-      const keyStr = JSON.stringify(keyValue);
-
-      // Check unique constraint
-      if (indexData.unique) {
-        const existing = indexData.entries.get(keyStr);
-        if (existing && existing.size > 0) {
-          throw new CongoDuplicateKeyError(
-            `E11000 duplicate key error collection: ${this.dbName}.${this.collName} index: ${name}`,
-            indexData.key as Record<string, 1>,
-            keyValue
-          );
-        }
-      }
-
-      if (!indexData.entries.has(keyStr)) {
-        indexData.entries.set(keyStr, new Set());
-      }
-      indexData.entries.get(keyStr)!.add(doc._id.toHexString());
-    }
-  }
-
-  /**
-   * Update index entries after document update
-   */
-  async onUpdate(oldDoc: IStoredDocument, newDoc: IStoredDocument): Promise<void> {
-    await this.initialize();
-
-    for (const [name, indexData] of this.indexes) {
-      const oldKeyValue = this.extractKeyValue(oldDoc, indexData.key);
-      const newKeyValue = this.extractKeyValue(newDoc, indexData.key);
-      const oldKeyStr = JSON.stringify(oldKeyValue);
-      const newKeyStr = JSON.stringify(newKeyValue);
-
-      // Remove old entry if key changed
-      if (oldKeyStr !== newKeyStr) {
-        if (oldKeyValue !== null || !indexData.sparse) {
-          const oldSet = indexData.entries.get(oldKeyStr);
-          if (oldSet) {
-            oldSet.delete(oldDoc._id.toHexString());
-            if (oldSet.size === 0) {
-              indexData.entries.delete(oldKeyStr);
-            }
-          }
-        }
-
-        // Add new entry
-        if (newKeyValue !== null || !indexData.sparse) {
-          // Check unique constraint
-          if (indexData.unique) {
-            const existing = indexData.entries.get(newKeyStr);
-            if (existing && existing.size > 0) {
-              throw new CongoDuplicateKeyError(
-                `E11000 duplicate key error collection: ${this.dbName}.${this.collName} index: ${name}`,
-                indexData.key as Record<string, 1>,
-                newKeyValue
-              );
-            }
-          }
-
-          if (!indexData.entries.has(newKeyStr)) {
-            indexData.entries.set(newKeyStr, new Set());
-          }
-          indexData.entries.get(newKeyStr)!.add(newDoc._id.toHexString());
-        }
-      }
-    }
-  }
-
-  /**
-   * Update index entries after document delete
-   */
-  async onDelete(doc: IStoredDocument): Promise<void> {
-    await this.initialize();
-
-    for (const indexData of this.indexes.values()) {
-      const keyValue = this.extractKeyValue(doc, indexData.key);
-
-      if (keyValue === null && indexData.sparse) {
-        continue;
-      }
-
-      const keyStr = JSON.stringify(keyValue);
-      const set = indexData.entries.get(keyStr);
-      if (set) {
-        set.delete(doc._id.toHexString());
-        if (set.size === 0) {
-          indexData.entries.delete(keyStr);
-        }
-      }
-    }
-  }
-
-  /**
-   * Find the best index for a query
-   */
-  selectIndex(filter: Document): { name: string; data: IIndexData } | null {
-    if (!filter || Object.keys(filter).length === 0) {
-      return null;
-    }
-
-    // Get filter fields
-    const filterFields = new Set(this.getFilterFields(filter));
-
-    // Score each index
-    let bestIndex: { name: string; data: IIndexData } | null = null;
-    let bestScore = 0;
-
-    for (const [name, indexData] of this.indexes) {
-      const indexFields = Object.keys(indexData.key);
-      let score = 0;
-
-      // Count how many index fields are in the filter
-      for (const field of indexFields) {
-        if (filterFields.has(field)) {
-          score++;
-        } else {
-          break; // Index fields must be contiguous
-        }
-      }
-
-      // Prefer unique indexes
-      if (indexData.unique && score > 0) {
-        score += 0.5;
-      }
-
-      if (score > bestScore) {
-        bestScore = score;
-        bestIndex = { name, data: indexData };
-      }
-    }
-
-    return bestIndex;
-  }
-
-  /**
-   * Use index to find candidate document IDs
-   */
-  async findCandidateIds(filter: Document): Promise<Set<string> | null> {
-    await this.initialize();
-
-    const index = this.selectIndex(filter);
-    if (!index) return null;
-
-    // Try to use the index for equality matches
-    const indexFields = Object.keys(index.data.key);
-    const equalityValues: Record<string, any> = {};
-
-    for (const field of indexFields) {
-      const filterValue = this.getFilterValue(filter, field);
-      if (filterValue === undefined) break;
-
-      // Only use equality matches for index lookup
-      if (typeof filterValue === 'object' && filterValue !== null) {
-        if (filterValue.$eq !== undefined) {
-          equalityValues[field] = filterValue.$eq;
-        } else if (filterValue.$in !== undefined) {
-          // Handle $in with multiple lookups
-          const results = new Set<string>();
-          for (const val of filterValue.$in) {
-            equalityValues[field] = val;
-            const keyStr = JSON.stringify(this.buildKeyValue(equalityValues, index.data.key));
-            const ids = index.data.entries.get(keyStr);
-            if (ids) {
-              for (const id of ids) {
-                results.add(id);
-              }
-            }
-          }
-          return results;
-        } else {
-          break; // Non-equality operator, stop here
-        }
-      } else {
-        equalityValues[field] = filterValue;
-      }
-    }
-
-    if (Object.keys(equalityValues).length === 0) {
-      return null;
-    }
-
-    const keyStr = JSON.stringify(this.buildKeyValue(equalityValues, index.data.key));
-    return index.data.entries.get(keyStr) || new Set();
-  }
-
-  // ============================================================================
-  // Helper Methods
-  // ============================================================================
-
-  private generateIndexName(key: Record<string, any>): string {
-    return Object.entries(key)
-      .map(([field, dir]) => `${field}_${dir}`)
-      .join('_');
-  }
-
-  private extractKeyValue(doc: Document, key: Record<string, any>): any {
-    const values: any[] = [];
-
-    for (const field of Object.keys(key)) {
-      const value = QueryEngine.getNestedValue(doc, field);
-      values.push(value === undefined ? null : value);
-    }
-
-    // For single-field index, return the value directly
-    if (values.length === 1) {
-      return values[0];
-    }
-
-    return values;
-  }
-
-  private buildKeyValue(values: Record<string, any>, key: Record<string, any>): any {
-    const result: any[] = [];
-
-    for (const field of Object.keys(key)) {
-      result.push(values[field] !== undefined ? values[field] : null);
-    }
-
-    if (result.length === 1) {
-      return result[0];
-    }
-
-    return result;
-  }
-
-  private getFilterFields(filter: Document, prefix = ''): string[] {
-    const fields: string[] = [];
-
-    for (const [key, value] of Object.entries(filter)) {
-      if (key.startsWith('$')) {
-        // Logical operator
-        if (key === '$and' || key === '$or' || key === '$nor') {
-          for (const subFilter of value as Document[]) {
-            fields.push(...this.getFilterFields(subFilter, prefix));
-          }
-        }
-      } else {
-        const fullKey = prefix ? `${prefix}.${key}` : key;
-        fields.push(fullKey);
-
-        // Check for nested filters
-        if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
-          const subKeys = Object.keys(value);
-          if (subKeys.length > 0 && !subKeys[0].startsWith('$')) {
-            fields.push(...this.getFilterFields(value, fullKey));
-          }
-        }
-      }
-    }
-
-    return fields;
-  }
-
-  private getFilterValue(filter: Document, field: string): any {
-    // Handle dot notation
-    const parts = field.split('.');
-    let current: any = filter;
-
-    for (const part of parts) {
-      if (current === null || current === undefined) {
-        return undefined;
-      }
-      current = current[part];
-    }
-
-    return current;
-  }
-}

ts/index.ts

@@ -1,74 +1,14 @@
 import { commitinfo } from './00_commitinfo_data.js';
-import * as plugins from './smartmongo.plugins.js';
 
-// Export CongoDB module
-export * as congodb from './congodb/index.js';
+// Export SmartMongo from ts_mongotools
+export { SmartMongo } from './ts_mongotools/index.js';
 
-export class SmartMongo {
-  // STATIC
-  public static async createAndStart(replCountArg: number = 1) {
-    const smartMongoInstance = new SmartMongo();
-    await smartMongoInstance.start(replCountArg);
-    return smartMongoInstance;
-  }
+// Export TsmDB module
+export * as tsmdb from './ts_tsmdb/index.js';
 
-  // INSTANCE
-  private _readyDeferred = plugins.smartpromise.defer();
-  public readyPromise = this._readyDeferred.promise;
-  public mongoReplicaSet: plugins.mongoPlugin.MongoMemoryReplSet;
+// Export LocalTsmDb from ts_local
+export { LocalTsmDb } from './ts_local/index.js';
+export type { ILocalTsmDbOptions } from './ts_local/index.js';
 
-  constructor() {}
-
-  public async start(countArg: number = 1) {
-    this.mongoReplicaSet = await plugins.mongoPlugin.MongoMemoryReplSet.create({
-      replSet: { count: countArg },
-      instanceOpts: [
-        {
-          storageEngine: 'wiredTiger',
-        },
-      ],
-    });
-    this._readyDeferred.resolve();
-    console.log(`mongoReplicaSet with ${countArg} replicas started.`);
-    console.log(`@pushrocks/smartmongo version ${commitinfo.version}`);
-  }
-
-  /**
-   * returns a mongo descriptor for modules like
-   * @pushrocks/smartfile.
-   */
-  public async getMongoDescriptor(): Promise<plugins.smartdata.IMongoDescriptor> {
-    await this.readyPromise;
-    return {
-      mongoDbName: `smartmongo_testdatabase`,
-      mongoDbUrl: this.mongoReplicaSet.getUri(),
-    };
-  }
-
-  /**
-   * stops the smartmongo instance
-   * and cleans up after itself
-   */
-  public async stop() {
-    await this.mongoReplicaSet.stop();
-    await this.mongoReplicaSet.cleanup();
-  }
-
-  /**
-   * like stop() but allows you to actually store
-   * the database on disk
-   */
-  public async stopAndDumpToDir(
-    dirArg: string,
-    nameFunctionArg?: (doc: any) => string,
-    emptyDirArg = true,
-  ) {
-    const mongodumpInstance = new plugins.mongodump.MongoDump();
-    const mongodumpTarget = await mongodumpInstance.addMongoTargetByMongoDescriptor(
-      await this.getMongoDescriptor(),
-    );
-    await mongodumpTarget.dumpAllCollectionsToDir(dirArg, nameFunctionArg, emptyDirArg);
-    await mongodumpInstance.stop();
-    await this.stop();
-  }
-}
+// Export commitinfo
+export { commitinfo };

ts/ts_local/classes.localtsmdb.ts

@@ -0,0 +1,138 @@
+import * as plugins from './plugins.js';
+import { TsmdbServer } from '../ts_tsmdb/index.js';
+import type { MongoClient } from 'mongodb';
+
+export interface ILocalTsmDbOptions {
+  folderPath: string;
+  port?: number;
+  host?: string;
+}
+
+/**
+ * LocalTsmDb - Convenience class for local MongoDB-compatible database
+ *
+ * This class wraps TsmdbServer and provides a simple interface for
+ * starting a local file-based MongoDB-compatible server and connecting to it.
+ *
+ * @example
+ * ```typescript
+ * import { LocalTsmDb } from '@push.rocks/smartmongo';
+ *
+ * const db = new LocalTsmDb({ folderPath: './data' });
+ * const client = await db.start();
+ *
+ * // Use the MongoDB client
+ * const collection = client.db('mydb').collection('users');
+ * await collection.insertOne({ name: 'Alice' });
+ *
+ * // When done
+ * await db.stop();
+ * ```
+ */
+export class LocalTsmDb {
+  private options: ILocalTsmDbOptions;
+  private server: TsmdbServer | null = null;
+  private client: MongoClient | null = null;
+
+  constructor(options: ILocalTsmDbOptions) {
+    this.options = options;
+  }
+
+  /**
+   * Find an available port starting from the given port
+   */
+  private async findAvailablePort(startPort = 27017): Promise<number> {
+    return new Promise((resolve, reject) => {
+      const server = plugins.net.createServer();
+      server.listen(startPort, '127.0.0.1', () => {
+        const addr = server.address();
+        const port = typeof addr === 'object' && addr ? addr.port : startPort;
+        server.close(() => resolve(port));
+      });
+      server.on('error', () => {
+        this.findAvailablePort(startPort + 1).then(resolve).catch(reject);
+      });
+    });
+  }
+
+  /**
+   * Start the local TsmDB server and return a connected MongoDB client
+   */
+  async start(): Promise<MongoClient> {
+    if (this.server && this.client) {
+      throw new Error('LocalTsmDb is already running');
+    }
+
+    const port = this.options.port ?? await this.findAvailablePort();
+    const host = this.options.host ?? '127.0.0.1';
+
+    this.server = new TsmdbServer({
+      port,
+      host,
+      storage: 'file',
+      storagePath: this.options.folderPath,
+    });
+    await this.server.start();
+
+    // Dynamically import mongodb to avoid requiring it as a hard dependency
+    const mongodb = await import('mongodb');
+    this.client = new mongodb.MongoClient(this.server.getConnectionUri(), {
+      directConnection: true,
+      serverSelectionTimeoutMS: 5000,
+    });
+    await this.client.connect();
+
+    return this.client;
+  }
+
+  /**
+   * Get the MongoDB client (throws if not started)
+   */
+  getClient(): MongoClient {
+    if (!this.client) {
+      throw new Error('LocalTsmDb is not running. Call start() first.');
+    }
+    return this.client;
+  }
+
+  /**
+   * Get the underlying TsmdbServer instance (throws if not started)
+   */
+  getServer(): TsmdbServer {
+    if (!this.server) {
+      throw new Error('LocalTsmDb is not running. Call start() first.');
+    }
+    return this.server;
+  }
+
+  /**
+   * Get the connection URI
+   */
+  getConnectionUri(): string {
+    if (!this.server) {
+      throw new Error('LocalTsmDb is not running. Call start() first.');
+    }
+    return this.server.getConnectionUri();
+  }
+
+  /**
+   * Check if the server is running
+   */
+  get running(): boolean {
+    return this.server !== null && this.server.running;
+  }
+
+  /**
+   * Stop the local TsmDB server and close the client connection
+   */
+  async stop(): Promise<void> {
+    if (this.client) {
+      await this.client.close();
+      this.client = null;
+    }
+    if (this.server) {
+      await this.server.stop();
+      this.server = null;
+    }
+  }
+}

ts/ts_local/index.ts

@@ -0,0 +1,2 @@
+export { LocalTsmDb } from './classes.localtsmdb.js';
+export type { ILocalTsmDbOptions } from './classes.localtsmdb.js';

ts/ts_local/plugins.ts

@@ -0,0 +1,4 @@
+import * as smartpromise from '@push.rocks/smartpromise';
+import * as net from 'net';
+
+export { smartpromise, net };

ts/ts_mongotools/classes.smartmongo.ts

@@ -0,0 +1,71 @@
+import { commitinfo } from '../00_commitinfo_data.js';
+import * as plugins from './plugins.js';
+
+export class SmartMongo {
+  // STATIC
+  public static async createAndStart(replCountArg: number = 1) {
+    const smartMongoInstance = new SmartMongo();
+    await smartMongoInstance.start(replCountArg);
+    return smartMongoInstance;
+  }
+
+  // INSTANCE
+  private _readyDeferred = plugins.smartpromise.defer();
+  public readyPromise = this._readyDeferred.promise;
+  public mongoReplicaSet: plugins.mongoPlugin.MongoMemoryReplSet;
+
+  constructor() {}
+
+  public async start(countArg: number = 1) {
+    this.mongoReplicaSet = await plugins.mongoPlugin.MongoMemoryReplSet.create({
+      replSet: { count: countArg },
+      instanceOpts: [
+        {
+          storageEngine: 'wiredTiger',
+        },
+      ],
+    });
+    this._readyDeferred.resolve();
+    console.log(`mongoReplicaSet with ${countArg} replicas started.`);
+    console.log(`@pushrocks/smartmongo version ${commitinfo.version}`);
+  }
+
+  /**
+   * returns a mongo descriptor for modules like
+   * @pushrocks/smartfile.
+   */
+  public async getMongoDescriptor(): Promise<plugins.smartdata.IMongoDescriptor> {
+    await this.readyPromise;
+    return {
+      mongoDbName: `smartmongo_testdatabase`,
+      mongoDbUrl: this.mongoReplicaSet.getUri(),
+    };
+  }
+
+  /**
+   * stops the smartmongo instance
+   * and cleans up after itself
+   */
+  public async stop() {
+    await this.mongoReplicaSet.stop();
+    await this.mongoReplicaSet.cleanup();
+  }
+
+  /**
+   * like stop() but allows you to actually store
+   * the database on disk
+   */
+  public async stopAndDumpToDir(
+    dirArg: string,
+    nameFunctionArg?: (doc: any) => string,
+    emptyDirArg = true,
+  ) {
+    const mongodumpInstance = new plugins.mongodump.MongoDump();
+    const mongodumpTarget = await mongodumpInstance.addMongoTargetByMongoDescriptor(
+      await this.getMongoDescriptor(),
+    );
+    await mongodumpTarget.dumpAllCollectionsToDir(dirArg, nameFunctionArg, emptyDirArg);
+    await mongodumpInstance.stop();
+    await this.stop();
+  }
+}

ts/ts_mongotools/index.ts

@@ -0,0 +1,2 @@
+export * from './plugins.js';
+export { SmartMongo } from './classes.smartmongo.js';

ts/ts_tsmdb/engine/AggregationEngine.ts

@@ -1,4 +1,4 @@
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 import type { Document, IStoredDocument, IAggregateOptions } from '../types/interfaces.js';
 
 // Import mingo Aggregator

ts/ts_tsmdb/engine/IndexEngine.ts

@@ -0,0 +1,798 @@
+import * as plugins from '../plugins.js';
+import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
+
+// Simple B-Tree implementation for range queries
+// Since sorted-btree has ESM/CJS interop issues, we use a simple custom implementation
+class SimpleBTree<K, V> {
+  private entries: Map<string, { key: K; value: V }> = new Map();
+  private sortedKeys: K[] = [];
+  private comparator: (a: K, b: K) => number;
+
+  constructor(_unused?: undefined, comparator?: (a: K, b: K) => number) {
+    this.comparator = comparator || ((a: K, b: K) => {
+      if (a < b) return -1;
+      if (a > b) return 1;
+      return 0;
+    });
+  }
+
+  private keyToString(key: K): string {
+    return JSON.stringify(key);
+  }
+
+  set(key: K, value: V): boolean {
+    const keyStr = this.keyToString(key);
+    const existed = this.entries.has(keyStr);
+    this.entries.set(keyStr, { key, value });
+
+    if (!existed) {
+      // Insert in sorted order
+      const idx = this.sortedKeys.findIndex(k => this.comparator(k, key) > 0);
+      if (idx === -1) {
+        this.sortedKeys.push(key);
+      } else {
+        this.sortedKeys.splice(idx, 0, key);
+      }
+    }
+    return !existed;
+  }
+
+  get(key: K): V | undefined {
+    const entry = this.entries.get(this.keyToString(key));
+    return entry?.value;
+  }
+
+  delete(key: K): boolean {
+    const keyStr = this.keyToString(key);
+    if (this.entries.has(keyStr)) {
+      this.entries.delete(keyStr);
+      const idx = this.sortedKeys.findIndex(k => this.comparator(k, key) === 0);
+      if (idx !== -1) {
+        this.sortedKeys.splice(idx, 1);
+      }
+      return true;
+    }
+    return false;
+  }
+
+  forRange(
+    lowKey: K | undefined,
+    highKey: K | undefined,
+    lowInclusive: boolean,
+    highInclusive: boolean,
+    callback: (value: V, key: K) => void
+  ): void {
+    for (const key of this.sortedKeys) {
+      // Check low bound
+      if (lowKey !== undefined) {
+        const cmp = this.comparator(key, lowKey);
+        if (cmp < 0) continue;
+        if (cmp === 0 && !lowInclusive) continue;
+      }
+
+      // Check high bound
+      if (highKey !== undefined) {
+        const cmp = this.comparator(key, highKey);
+        if (cmp > 0) break;
+        if (cmp === 0 && !highInclusive) break;
+      }
+
+      const entry = this.entries.get(this.keyToString(key));
+      if (entry) {
+        callback(entry.value, key);
+      }
+    }
+  }
+}
+import type {
+  Document,
+  IStoredDocument,
+  IIndexSpecification,
+  IIndexInfo,
+  ICreateIndexOptions,
+} from '../types/interfaces.js';
+import { TsmdbDuplicateKeyError, TsmdbIndexError } from '../errors/TsmdbErrors.js';
+import { QueryEngine } from './QueryEngine.js';
+
+/**
+ * Comparator for B-Tree that handles mixed types consistently
+ */
+function indexKeyComparator(a: any, b: any): number {
+  // Handle null/undefined
+  if (a === null || a === undefined) {
+    if (b === null || b === undefined) return 0;
+    return -1;
+  }
+  if (b === null || b === undefined) return 1;
+
+  // Handle arrays (compound keys)
+  if (Array.isArray(a) && Array.isArray(b)) {
+    for (let i = 0; i < Math.max(a.length, b.length); i++) {
+      const cmp = indexKeyComparator(a[i], b[i]);
+      if (cmp !== 0) return cmp;
+    }
+    return 0;
+  }
+
+  // Handle ObjectId
+  if (a instanceof plugins.bson.ObjectId && b instanceof plugins.bson.ObjectId) {
+    return a.toHexString().localeCompare(b.toHexString());
+  }
+
+  // Handle Date
+  if (a instanceof Date && b instanceof Date) {
+    return a.getTime() - b.getTime();
+  }
+
+  // Handle different types - use type ordering (null < number < string < object)
+  const typeOrder = (v: any): number => {
+    if (v === null || v === undefined) return 0;
+    if (typeof v === 'number') return 1;
+    if (typeof v === 'string') return 2;
+    if (typeof v === 'boolean') return 3;
+    if (v instanceof Date) return 4;
+    if (v instanceof plugins.bson.ObjectId) return 5;
+    return 6;
+  };
+
+  const typeA = typeOrder(a);
+  const typeB = typeOrder(b);
+  if (typeA !== typeB) return typeA - typeB;
+
+  // Same type comparison
+  if (typeof a === 'number') return a - b;
+  if (typeof a === 'string') return a.localeCompare(b);
+  if (typeof a === 'boolean') return (a ? 1 : 0) - (b ? 1 : 0);
+
+  // Fallback to string comparison
+  return String(a).localeCompare(String(b));
+}
+
+/**
+ * Index data structure using B-Tree for range queries
+ */
+interface IIndexData {
+  name: string;
+  key: Record<string, 1 | -1 | string>;
+  unique: boolean;
+  sparse: boolean;
+  expireAfterSeconds?: number;
+  // B-Tree for ordered index lookups (supports range queries)
+  btree: SimpleBTree<any, Set<string>>;
+  // Hash map for fast equality lookups
+  hashMap: Map<string, Set<string>>;
+}
+
+/**
+ * Index engine for managing indexes and query optimization
+ */
+export class IndexEngine {
+  private dbName: string;
+  private collName: string;
+  private storage: IStorageAdapter;
+  private indexes: Map<string, IIndexData> = new Map();
+  private initialized = false;
+
+  constructor(dbName: string, collName: string, storage: IStorageAdapter) {
+    this.dbName = dbName;
+    this.collName = collName;
+    this.storage = storage;
+  }
+
+  /**
+   * Initialize indexes from storage
+   */
+  async initialize(): Promise<void> {
+    if (this.initialized) return;
+
+    const storedIndexes = await this.storage.getIndexes(this.dbName, this.collName);
+    const documents = await this.storage.findAll(this.dbName, this.collName);
+
+    for (const indexSpec of storedIndexes) {
+      const indexData: IIndexData = {
+        name: indexSpec.name,
+        key: indexSpec.key,
+        unique: indexSpec.unique || false,
+        sparse: indexSpec.sparse || false,
+        expireAfterSeconds: indexSpec.expireAfterSeconds,
+        btree: new SimpleBTree<any, Set<string>>(undefined, indexKeyComparator),
+        hashMap: new Map(),
+      };
+
+      // Build index entries
+      for (const doc of documents) {
+        const keyValue = this.extractKeyValue(doc, indexSpec.key);
+        if (keyValue !== null || !indexData.sparse) {
+          const keyStr = JSON.stringify(keyValue);
+
+          // Add to hash map
+          if (!indexData.hashMap.has(keyStr)) {
+            indexData.hashMap.set(keyStr, new Set());
+          }
+          indexData.hashMap.get(keyStr)!.add(doc._id.toHexString());
+
+          // Add to B-tree
+          const existing = indexData.btree.get(keyValue);
+          if (existing) {
+            existing.add(doc._id.toHexString());
+          } else {
+            indexData.btree.set(keyValue, new Set([doc._id.toHexString()]));
+          }
+        }
+      }
+
+      this.indexes.set(indexSpec.name, indexData);
+    }
+
+    this.initialized = true;
+  }
+
+  /**
+   * Create a new index
+   */
+  async createIndex(
+    key: Record<string, 1 | -1 | 'text' | '2dsphere'>,
+    options?: ICreateIndexOptions
+  ): Promise<string> {
+    await this.initialize();
+
+    // Generate index name if not provided
+    const name = options?.name || this.generateIndexName(key);
+
+    // Check if index already exists
+    if (this.indexes.has(name)) {
+      return name;
+    }
+
+    // Create index data structure
+    const indexData: IIndexData = {
+      name,
+      key: key as Record<string, 1 | -1 | string>,
+      unique: options?.unique || false,
+      sparse: options?.sparse || false,
+      expireAfterSeconds: options?.expireAfterSeconds,
+      btree: new SimpleBTree<any, Set<string>>(undefined, indexKeyComparator),
+      hashMap: new Map(),
+    };
+
+    // Build index from existing documents
+    const documents = await this.storage.findAll(this.dbName, this.collName);
+
+    for (const doc of documents) {
+      const keyValue = this.extractKeyValue(doc, key);
+
+      if (keyValue === null && indexData.sparse) {
+        continue;
+      }
+
+      const keyStr = JSON.stringify(keyValue);
+
+      if (indexData.unique && indexData.hashMap.has(keyStr)) {
+        throw new TsmdbDuplicateKeyError(
+          `E11000 duplicate key error index: ${this.dbName}.${this.collName}.$${name}`,
+          key as Record<string, 1>,
+          keyValue
+        );
+      }
+
+      // Add to hash map
+      if (!indexData.hashMap.has(keyStr)) {
+        indexData.hashMap.set(keyStr, new Set());
+      }
+      indexData.hashMap.get(keyStr)!.add(doc._id.toHexString());
+
+      // Add to B-tree
+      const existing = indexData.btree.get(keyValue);
+      if (existing) {
+        existing.add(doc._id.toHexString());
+      } else {
+        indexData.btree.set(keyValue, new Set([doc._id.toHexString()]));
+      }
+    }
+
+    // Store index
+    this.indexes.set(name, indexData);
+    await this.storage.saveIndex(this.dbName, this.collName, name, {
+      key,
+      unique: options?.unique,
+      sparse: options?.sparse,
+      expireAfterSeconds: options?.expireAfterSeconds,
+    });
+
+    return name;
+  }
+
+  /**
+   * Drop an index
+   */
+  async dropIndex(name: string): Promise<void> {
+    await this.initialize();
+
+    if (name === '_id_') {
+      throw new TsmdbIndexError('cannot drop _id index');
+    }
+
+    if (!this.indexes.has(name)) {
+      throw new TsmdbIndexError(`index not found: ${name}`);
+    }
+
+    this.indexes.delete(name);
+    await this.storage.dropIndex(this.dbName, this.collName, name);
+  }
+
+  /**
+   * Drop all indexes except _id
+   */
+  async dropAllIndexes(): Promise<void> {
+    await this.initialize();
+
+    const names = Array.from(this.indexes.keys()).filter(n => n !== '_id_');
+    for (const name of names) {
+      this.indexes.delete(name);
+      await this.storage.dropIndex(this.dbName, this.collName, name);
+    }
+  }
+
+  /**
+   * List all indexes
+   */
+  async listIndexes(): Promise<IIndexInfo[]> {
+    await this.initialize();
+
+    return Array.from(this.indexes.values()).map(idx => ({
+      v: 2,
+      key: idx.key,
+      name: idx.name,
+      unique: idx.unique || undefined,
+      sparse: idx.sparse || undefined,
+      expireAfterSeconds: idx.expireAfterSeconds,
+    }));
+  }
+
+  /**
+   * Check if an index exists
+   */
+  async indexExists(name: string): Promise<boolean> {
+    await this.initialize();
+    return this.indexes.has(name);
+  }
+
+  /**
+   * Update index entries after document insert
+   */
+  async onInsert(doc: IStoredDocument): Promise<void> {
+    await this.initialize();
+
+    for (const [name, indexData] of this.indexes) {
+      const keyValue = this.extractKeyValue(doc, indexData.key);
+
+      if (keyValue === null && indexData.sparse) {
+        continue;
+      }
+
+      const keyStr = JSON.stringify(keyValue);
+
+      // Check unique constraint
+      if (indexData.unique) {
+        const existing = indexData.hashMap.get(keyStr);
+        if (existing && existing.size > 0) {
+          throw new TsmdbDuplicateKeyError(
+            `E11000 duplicate key error collection: ${this.dbName}.${this.collName} index: ${name}`,
+            indexData.key as Record<string, 1>,
+            keyValue
+          );
+        }
+      }
+
+      // Add to hash map
+      if (!indexData.hashMap.has(keyStr)) {
+        indexData.hashMap.set(keyStr, new Set());
+      }
+      indexData.hashMap.get(keyStr)!.add(doc._id.toHexString());
+
+      // Add to B-tree
+      const btreeSet = indexData.btree.get(keyValue);
+      if (btreeSet) {
+        btreeSet.add(doc._id.toHexString());
+      } else {
+        indexData.btree.set(keyValue, new Set([doc._id.toHexString()]));
+      }
+    }
+  }
+
+  /**
+   * Update index entries after document update
+   */
+  async onUpdate(oldDoc: IStoredDocument, newDoc: IStoredDocument): Promise<void> {
+    await this.initialize();
+
+    for (const [name, indexData] of this.indexes) {
+      const oldKeyValue = this.extractKeyValue(oldDoc, indexData.key);
+      const newKeyValue = this.extractKeyValue(newDoc, indexData.key);
+      const oldKeyStr = JSON.stringify(oldKeyValue);
+      const newKeyStr = JSON.stringify(newKeyValue);
+
+      // Remove old entry if key changed
+      if (oldKeyStr !== newKeyStr) {
+        if (oldKeyValue !== null || !indexData.sparse) {
+          // Remove from hash map
+          const oldHashSet = indexData.hashMap.get(oldKeyStr);
+          if (oldHashSet) {
+            oldHashSet.delete(oldDoc._id.toHexString());
+            if (oldHashSet.size === 0) {
+              indexData.hashMap.delete(oldKeyStr);
+            }
+          }
+
+          // Remove from B-tree
+          const oldBtreeSet = indexData.btree.get(oldKeyValue);
+          if (oldBtreeSet) {
+            oldBtreeSet.delete(oldDoc._id.toHexString());
+            if (oldBtreeSet.size === 0) {
+              indexData.btree.delete(oldKeyValue);
+            }
+          }
+        }
+
+        // Add new entry
+        if (newKeyValue !== null || !indexData.sparse) {
+          // Check unique constraint
+          if (indexData.unique) {
+            const existing = indexData.hashMap.get(newKeyStr);
+            if (existing && existing.size > 0) {
+              throw new TsmdbDuplicateKeyError(
+                `E11000 duplicate key error collection: ${this.dbName}.${this.collName} index: ${name}`,
+                indexData.key as Record<string, 1>,
+                newKeyValue
+              );
+            }
+          }
+
+          // Add to hash map
+          if (!indexData.hashMap.has(newKeyStr)) {
+            indexData.hashMap.set(newKeyStr, new Set());
+          }
+          indexData.hashMap.get(newKeyStr)!.add(newDoc._id.toHexString());
+
+          // Add to B-tree
+          const newBtreeSet = indexData.btree.get(newKeyValue);
+          if (newBtreeSet) {
+            newBtreeSet.add(newDoc._id.toHexString());
+          } else {
+            indexData.btree.set(newKeyValue, new Set([newDoc._id.toHexString()]));
+          }
+        }
+      }
+    }
+  }
+
+  /**
+   * Update index entries after document delete
+   */
+  async onDelete(doc: IStoredDocument): Promise<void> {
+    await this.initialize();
+
+    for (const indexData of this.indexes.values()) {
+      const keyValue = this.extractKeyValue(doc, indexData.key);
+
+      if (keyValue === null && indexData.sparse) {
+        continue;
+      }
+
+      const keyStr = JSON.stringify(keyValue);
+
+      // Remove from hash map
+      const hashSet = indexData.hashMap.get(keyStr);
+      if (hashSet) {
+        hashSet.delete(doc._id.toHexString());
+        if (hashSet.size === 0) {
+          indexData.hashMap.delete(keyStr);
+        }
+      }
+
+      // Remove from B-tree
+      const btreeSet = indexData.btree.get(keyValue);
+      if (btreeSet) {
+        btreeSet.delete(doc._id.toHexString());
+        if (btreeSet.size === 0) {
+          indexData.btree.delete(keyValue);
+        }
+      }
+    }
+  }
+
+  /**
+   * Find the best index for a query
+   */
+  selectIndex(filter: Document): { name: string; data: IIndexData } | null {
+    if (!filter || Object.keys(filter).length === 0) {
+      return null;
+    }
+
+    // Get filter fields and operators
+    const filterInfo = this.analyzeFilter(filter);
+
+    // Score each index
+    let bestIndex: { name: string; data: IIndexData } | null = null;
+    let bestScore = 0;
+
+    for (const [name, indexData] of this.indexes) {
+      const indexFields = Object.keys(indexData.key);
+      let score = 0;
+
+      // Count how many index fields can be used
+      for (const field of indexFields) {
+        const info = filterInfo.get(field);
+        if (!info) break;
+
+        // Equality is best
+        if (info.equality) {
+          score += 2;
+        } else if (info.range) {
+          // Range queries can use B-tree
+          score += 1;
+        } else if (info.in) {
+          score += 1.5;
+        } else {
+          break;
+        }
+      }
+
+      // Prefer unique indexes
+      if (indexData.unique && score > 0) {
+        score += 0.5;
+      }
+
+      if (score > bestScore) {
+        bestScore = score;
+        bestIndex = { name, data: indexData };
+      }
+    }
+
+    return bestIndex;
+  }
+
+  /**
+   * Analyze filter to extract field operators
+   */
+  private analyzeFilter(filter: Document): Map<string, { equality: boolean; range: boolean; in: boolean; ops: Record<string, any> }> {
+    const result = new Map<string, { equality: boolean; range: boolean; in: boolean; ops: Record<string, any> }>();
+
+    for (const [key, value] of Object.entries(filter)) {
+      if (key.startsWith('$')) continue;
+
+      const info = { equality: false, range: false, in: false, ops: {} as Record<string, any> };
+
+      if (typeof value !== 'object' || value === null || value instanceof plugins.bson.ObjectId || value instanceof Date) {
+        info.equality = true;
+        info.ops['$eq'] = value;
+      } else {
+        const ops = value as Record<string, any>;
+        if (ops.$eq !== undefined) {
+          info.equality = true;
+          info.ops['$eq'] = ops.$eq;
+        }
+        if (ops.$in !== undefined) {
+          info.in = true;
+          info.ops['$in'] = ops.$in;
+        }
+        if (ops.$gt !== undefined || ops.$gte !== undefined || ops.$lt !== undefined || ops.$lte !== undefined) {
+          info.range = true;
+          if (ops.$gt !== undefined) info.ops['$gt'] = ops.$gt;
+          if (ops.$gte !== undefined) info.ops['$gte'] = ops.$gte;
+          if (ops.$lt !== undefined) info.ops['$lt'] = ops.$lt;
+          if (ops.$lte !== undefined) info.ops['$lte'] = ops.$lte;
+        }
+      }
+
+      result.set(key, info);
+    }
+
+    return result;
+  }
+
+  /**
+   * Use index to find candidate document IDs (supports range queries with B-tree)
+   */
+  async findCandidateIds(filter: Document): Promise<Set<string> | null> {
+    await this.initialize();
+
+    const index = this.selectIndex(filter);
+    if (!index) return null;
+
+    const filterInfo = this.analyzeFilter(filter);
+    const indexFields = Object.keys(index.data.key);
+
+    // For single-field indexes with range queries, use B-tree
+    if (indexFields.length === 1) {
+      const field = indexFields[0];
+      const info = filterInfo.get(field);
+
+      if (info) {
+        // Handle equality using hash map (faster)
+        if (info.equality) {
+          const keyStr = JSON.stringify(info.ops['$eq']);
+          return index.data.hashMap.get(keyStr) || new Set();
+        }
+
+        // Handle $in using hash map
+        if (info.in) {
+          const results = new Set<string>();
+          for (const val of info.ops['$in']) {
+            const keyStr = JSON.stringify(val);
+            const ids = index.data.hashMap.get(keyStr);
+            if (ids) {
+              for (const id of ids) {
+                results.add(id);
+              }
+            }
+          }
+          return results;
+        }
+
+        // Handle range queries using B-tree
+        if (info.range) {
+          return this.findRangeCandidates(index.data, info.ops);
+        }
+      }
+    } else {
+      // For compound indexes, use hash map with partial key matching
+      const equalityValues: Record<string, any> = {};
+
+      for (const field of indexFields) {
+        const info = filterInfo.get(field);
+        if (!info) break;
+
+        if (info.equality) {
+          equalityValues[field] = info.ops['$eq'];
+        } else if (info.in) {
+          // Handle $in with multiple lookups
+          const results = new Set<string>();
+          for (const val of info.ops['$in']) {
+            equalityValues[field] = val;
+            const keyStr = JSON.stringify(this.buildKeyValue(equalityValues, index.data.key));
+            const ids = index.data.hashMap.get(keyStr);
+            if (ids) {
+              for (const id of ids) {
+                results.add(id);
+              }
+            }
+          }
+          return results;
+        } else {
+          break; // Non-equality/in operator, stop here
+        }
+      }
+
+      if (Object.keys(equalityValues).length > 0) {
+        const keyStr = JSON.stringify(this.buildKeyValue(equalityValues, index.data.key));
+        return index.data.hashMap.get(keyStr) || new Set();
+      }
+    }
+
+    return null;
+  }
+
+  /**
+   * Find candidates using B-tree range scan
+   */
+  private findRangeCandidates(indexData: IIndexData, ops: Record<string, any>): Set<string> {
+    const results = new Set<string>();
+
+    let lowKey: any = undefined;
+    let highKey: any = undefined;
+    let lowInclusive = true;
+    let highInclusive = true;
+
+    if (ops['$gt'] !== undefined) {
+      lowKey = ops['$gt'];
+      lowInclusive = false;
+    }
+    if (ops['$gte'] !== undefined) {
+      lowKey = ops['$gte'];
+      lowInclusive = true;
+    }
+    if (ops['$lt'] !== undefined) {
+      highKey = ops['$lt'];
+      highInclusive = false;
+    }
+    if (ops['$lte'] !== undefined) {
+      highKey = ops['$lte'];
+      highInclusive = true;
+    }
+
+    // Use B-tree range iteration
+    indexData.btree.forRange(lowKey, highKey, lowInclusive, highInclusive, (value, key) => {
+      if (value) {
+        for (const id of value) {
+          results.add(id);
+        }
+      }
+    });
+
+    return results;
+  }
+
+  // ============================================================================
+  // Helper Methods
+  // ============================================================================
+
+  private generateIndexName(key: Record<string, any>): string {
+    return Object.entries(key)
+      .map(([field, dir]) => `${field}_${dir}`)
+      .join('_');
+  }
+
+  private extractKeyValue(doc: Document, key: Record<string, any>): any {
+    const values: any[] = [];
+
+    for (const field of Object.keys(key)) {
+      const value = QueryEngine.getNestedValue(doc, field);
+      values.push(value === undefined ? null : value);
+    }
+
+    // For single-field index, return the value directly
+    if (values.length === 1) {
+      return values[0];
+    }
+
+    return values;
+  }
+
+  private buildKeyValue(values: Record<string, any>, key: Record<string, any>): any {
+    const result: any[] = [];
+
+    for (const field of Object.keys(key)) {
+      result.push(values[field] !== undefined ? values[field] : null);
+    }
+
+    if (result.length === 1) {
+      return result[0];
+    }
+
+    return result;
+  }
+
+  private getFilterFields(filter: Document, prefix = ''): string[] {
+    const fields: string[] = [];
+
+    for (const [key, value] of Object.entries(filter)) {
+      if (key.startsWith('$')) {
+        // Logical operator
+        if (key === '$and' || key === '$or' || key === '$nor') {
+          for (const subFilter of value as Document[]) {
+            fields.push(...this.getFilterFields(subFilter, prefix));
+          }
+        }
+      } else {
+        const fullKey = prefix ? `${prefix}.${key}` : key;
+        fields.push(fullKey);
+
+        // Check for nested filters
+        if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
+          const subKeys = Object.keys(value);
+          if (subKeys.length > 0 && !subKeys[0].startsWith('$')) {
+            fields.push(...this.getFilterFields(value, fullKey));
+          }
+        }
+      }
+    }
+
+    return fields;
+  }
+
+  private getFilterValue(filter: Document, field: string): any {
+    // Handle dot notation
+    const parts = field.split('.');
+    let current: any = filter;
+
+    for (const part of parts) {
+      if (current === null || current === undefined) {
+        return undefined;
+      }
+      current = current[part];
+    }
+
+    return current;
+  }
+}

ts/ts_tsmdb/engine/QueryEngine.ts

@@ -1,4 +1,4 @@
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 import type { Document, IStoredDocument, ISortSpecification, ISortDirection } from '../types/interfaces.js';
 
 // Import mingo Query class

ts/ts_tsmdb/engine/QueryPlanner.ts

@@ -0,0 +1,393 @@
+import * as plugins from '../plugins.js';
+import type { Document, IStoredDocument } from '../types/interfaces.js';
+import { IndexEngine } from './IndexEngine.js';
+
+/**
+ * Query execution plan types
+ */
+export type TQueryPlanType = 'IXSCAN' | 'COLLSCAN' | 'FETCH' | 'IXSCAN_RANGE';
+
+/**
+ * Represents a query execution plan
+ */
+export interface IQueryPlan {
+  /** The type of scan used */
+  type: TQueryPlanType;
+  /** Index name if using an index */
+  indexName?: string;
+  /** Index key specification */
+  indexKey?: Record<string, 1 | -1 | string>;
+  /** Whether the query can be fully satisfied by the index */
+  indexCovering: boolean;
+  /** Estimated selectivity (0-1, lower is more selective) */
+  selectivity: number;
+  /** Whether range operators are used */
+  usesRange: boolean;
+  /** Fields used from the index */
+  indexFieldsUsed: string[];
+  /** Filter conditions that must be applied post-index lookup */
+  residualFilter?: Document;
+  /** Explanation for debugging */
+  explanation: string;
+}
+
+/**
+ * Filter operator analysis
+ */
+interface IFilterOperatorInfo {
+  field: string;
+  operators: string[];
+  equality: boolean;
+  range: boolean;
+  in: boolean;
+  exists: boolean;
+  regex: boolean;
+  values: Record<string, any>;
+}
+
+/**
+ * QueryPlanner - Analyzes queries and selects optimal execution plans
+ */
+export class QueryPlanner {
+  private indexEngine: IndexEngine;
+
+  constructor(indexEngine: IndexEngine) {
+    this.indexEngine = indexEngine;
+  }
+
+  /**
+   * Generate an execution plan for a query filter
+   */
+  async plan(filter: Document): Promise<IQueryPlan> {
+    await this.indexEngine['initialize']();
+
+    // Empty filter = full collection scan
+    if (!filter || Object.keys(filter).length === 0) {
+      return {
+        type: 'COLLSCAN',
+        indexCovering: false,
+        selectivity: 1.0,
+        usesRange: false,
+        indexFieldsUsed: [],
+        explanation: 'No filter specified, full collection scan required',
+      };
+    }
+
+    // Analyze the filter
+    const operatorInfo = this.analyzeFilter(filter);
+
+    // Get available indexes
+    const indexes = await this.indexEngine.listIndexes();
+
+    // Score each index
+    let bestPlan: IQueryPlan | null = null;
+    let bestScore = -1;
+
+    for (const index of indexes) {
+      const plan = this.scoreIndex(index, operatorInfo, filter);
+      if (plan.selectivity < 1.0) {
+        const score = this.calculateScore(plan);
+        if (score > bestScore) {
+          bestScore = score;
+          bestPlan = plan;
+        }
+      }
+    }
+
+    // If no suitable index found, fall back to collection scan
+    if (!bestPlan || bestScore <= 0) {
+      return {
+        type: 'COLLSCAN',
+        indexCovering: false,
+        selectivity: 1.0,
+        usesRange: false,
+        indexFieldsUsed: [],
+        explanation: 'No suitable index found for this query',
+      };
+    }
+
+    return bestPlan;
+  }
+
+  /**
+   * Analyze filter to extract operator information per field
+   */
+  private analyzeFilter(filter: Document, prefix = ''): Map<string, IFilterOperatorInfo> {
+    const result = new Map<string, IFilterOperatorInfo>();
+
+    for (const [key, value] of Object.entries(filter)) {
+      // Skip logical operators at the top level
+      if (key.startsWith('$')) {
+        if (key === '$and' && Array.isArray(value)) {
+          // Merge $and conditions
+          for (const subFilter of value) {
+            const subInfo = this.analyzeFilter(subFilter, prefix);
+            for (const [field, info] of subInfo) {
+              if (result.has(field)) {
+                // Merge operators
+                const existing = result.get(field)!;
+                existing.operators.push(...info.operators);
+                existing.equality = existing.equality || info.equality;
+                existing.range = existing.range || info.range;
+                existing.in = existing.in || info.in;
+                Object.assign(existing.values, info.values);
+              } else {
+                result.set(field, info);
+              }
+            }
+          }
+        }
+        continue;
+      }
+
+      const fullKey = prefix ? `${prefix}.${key}` : key;
+      const info: IFilterOperatorInfo = {
+        field: fullKey,
+        operators: [],
+        equality: false,
+        range: false,
+        in: false,
+        exists: false,
+        regex: false,
+        values: {},
+      };
+
+      if (typeof value !== 'object' || value === null || value instanceof plugins.bson.ObjectId || value instanceof Date) {
+        // Direct equality
+        info.equality = true;
+        info.operators.push('$eq');
+        info.values['$eq'] = value;
+      } else if (Array.isArray(value)) {
+        // Array equality (rare, but possible)
+        info.equality = true;
+        info.operators.push('$eq');
+        info.values['$eq'] = value;
+      } else {
+        // Operator object
+        for (const [op, opValue] of Object.entries(value)) {
+          if (op.startsWith('$')) {
+            info.operators.push(op);
+            info.values[op] = opValue;
+
+            switch (op) {
+              case '$eq':
+                info.equality = true;
+                break;
+              case '$ne':
+              case '$not':
+                // These can use indexes but with low selectivity
+                break;
+              case '$in':
+                info.in = true;
+                break;
+              case '$nin':
+                // Can't efficiently use indexes
+                break;
+              case '$gt':
+              case '$gte':
+              case '$lt':
+              case '$lte':
+                info.range = true;
+                break;
+              case '$exists':
+                info.exists = true;
+                break;
+              case '$regex':
+                info.regex = true;
+                break;
+            }
+          } else {
+            // Nested object - recurse
+            const nestedInfo = this.analyzeFilter({ [op]: opValue }, fullKey);
+            for (const [nestedField, nestedFieldInfo] of nestedInfo) {
+              result.set(nestedField, nestedFieldInfo);
+            }
+          }
+        }
+      }
+
+      if (info.operators.length > 0) {
+        result.set(fullKey, info);
+      }
+    }
+
+    return result;
+  }
+
+  /**
+   * Score an index for the given filter
+   */
+  private scoreIndex(
+    index: { name: string; key: Record<string, any>; unique?: boolean; sparse?: boolean },
+    operatorInfo: Map<string, IFilterOperatorInfo>,
+    filter: Document
+  ): IQueryPlan {
+    const indexFields = Object.keys(index.key);
+    const usedFields: string[] = [];
+    let usesRange = false;
+    let canUseIndex = true;
+    let selectivity = 1.0;
+    let residualFilter: Document | undefined;
+
+    // Check each index field in order
+    for (const field of indexFields) {
+      const info = operatorInfo.get(field);
+      if (!info) {
+        // Index field not in filter - stop here
+        break;
+      }
+
+      usedFields.push(field);
+
+      // Calculate selectivity based on operator
+      if (info.equality) {
+        // Equality has high selectivity
+        selectivity *= 0.01; // Assume 1% match
+      } else if (info.in) {
+        // $in selectivity depends on array size
+        const inValues = info.values['$in'];
+        if (Array.isArray(inValues)) {
+          selectivity *= Math.min(0.5, inValues.length * 0.01);
+        } else {
+          selectivity *= 0.1;
+        }
+      } else if (info.range) {
+        // Range queries have moderate selectivity
+        selectivity *= 0.25;
+        usesRange = true;
+        // After range, can't use more index fields efficiently
+        break;
+      } else if (info.exists) {
+        // $exists can use sparse indexes
+        selectivity *= 0.5;
+      } else {
+        // Other operators may not be indexable
+        canUseIndex = false;
+        break;
+      }
+    }
+
+    if (!canUseIndex || usedFields.length === 0) {
+      return {
+        type: 'COLLSCAN',
+        indexCovering: false,
+        selectivity: 1.0,
+        usesRange: false,
+        indexFieldsUsed: [],
+        explanation: `Index ${index.name} cannot be used for this query`,
+      };
+    }
+
+    // Build residual filter for conditions not covered by index
+    const coveredFields = new Set(usedFields);
+    const residualConditions: Record<string, any> = {};
+    for (const [field, info] of operatorInfo) {
+      if (!coveredFields.has(field)) {
+        // This field isn't covered by the index
+        if (info.equality) {
+          residualConditions[field] = info.values['$eq'];
+        } else {
+          residualConditions[field] = info.values;
+        }
+      }
+    }
+
+    if (Object.keys(residualConditions).length > 0) {
+      residualFilter = residualConditions;
+    }
+
+    // Unique indexes have better selectivity for equality
+    if (index.unique && usedFields.length === indexFields.length) {
+      selectivity = Math.min(selectivity, 0.001); // At most 1 document
+    }
+
+    return {
+      type: usesRange ? 'IXSCAN_RANGE' : 'IXSCAN',
+      indexName: index.name,
+      indexKey: index.key,
+      indexCovering: Object.keys(residualConditions).length === 0,
+      selectivity,
+      usesRange,
+      indexFieldsUsed: usedFields,
+      residualFilter,
+      explanation: `Using index ${index.name} on fields [${usedFields.join(', ')}]`,
+    };
+  }
+
+  /**
+   * Calculate overall score for a plan (higher is better)
+   */
+  private calculateScore(plan: IQueryPlan): number {
+    let score = 0;
+
+    // Lower selectivity is better (fewer documents to fetch)
+    score += (1 - plan.selectivity) * 100;
+
+    // Index covering queries are best
+    if (plan.indexCovering) {
+      score += 50;
+    }
+
+    // More index fields used is better
+    score += plan.indexFieldsUsed.length * 10;
+
+    // Equality scans are better than range scans
+    if (!plan.usesRange) {
+      score += 20;
+    }
+
+    return score;
+  }
+
+  /**
+   * Explain a query - returns detailed plan information
+   */
+  async explain(filter: Document): Promise<{
+    queryPlanner: {
+      plannerVersion: number;
+      namespace: string;
+      indexFilterSet: boolean;
+      winningPlan: IQueryPlan;
+      rejectedPlans: IQueryPlan[];
+    };
+  }> {
+    await this.indexEngine['initialize']();
+
+    // Analyze the filter
+    const operatorInfo = this.analyzeFilter(filter);
+
+    // Get available indexes
+    const indexes = await this.indexEngine.listIndexes();
+
+    // Score all indexes
+    const plans: IQueryPlan[] = [];
+
+    for (const index of indexes) {
+      const plan = this.scoreIndex(index, operatorInfo, filter);
+      plans.push(plan);
+    }
+
+    // Add collection scan as fallback
+    plans.push({
+      type: 'COLLSCAN',
+      indexCovering: false,
+      selectivity: 1.0,
+      usesRange: false,
+      indexFieldsUsed: [],
+      explanation: 'Full collection scan',
+    });
+
+    // Sort by score (best first)
+    plans.sort((a, b) => this.calculateScore(b) - this.calculateScore(a));
+
+    return {
+      queryPlanner: {
+        plannerVersion: 1,
+        namespace: `${this.indexEngine['dbName']}.${this.indexEngine['collName']}`,
+        indexFilterSet: false,
+        winningPlan: plans[0],
+        rejectedPlans: plans.slice(1),
+      },
+    };
+  }
+}

ts/ts_tsmdb/engine/SessionEngine.ts

@@ -0,0 +1,292 @@
+import * as plugins from '../plugins.js';
+import type { TransactionEngine } from './TransactionEngine.js';
+
+/**
+ * Session state
+ */
+export interface ISession {
+  /** Session ID (UUID) */
+  id: string;
+  /** Timestamp when the session was created */
+  createdAt: number;
+  /** Timestamp of the last activity */
+  lastActivityAt: number;
+  /** Current transaction ID if any */
+  txnId?: string;
+  /** Transaction number for ordering */
+  txnNumber?: number;
+  /** Whether the session is in a transaction */
+  inTransaction: boolean;
+  /** Session metadata */
+  metadata?: Record<string, any>;
+}
+
+/**
+ * Session engine options
+ */
+export interface ISessionEngineOptions {
+  /** Session timeout in milliseconds (default: 30 minutes) */
+  sessionTimeoutMs?: number;
+  /** Interval to check for expired sessions in ms (default: 60 seconds) */
+  cleanupIntervalMs?: number;
+}
+
+/**
+ * Session engine for managing client sessions
+ * - Tracks session lifecycle (create, touch, end)
+ * - Links sessions to transactions
+ * - Auto-aborts transactions on session expiry
+ */
+export class SessionEngine {
+  private sessions: Map<string, ISession> = new Map();
+  private sessionTimeoutMs: number;
+  private cleanupInterval?: ReturnType<typeof setInterval>;
+  private transactionEngine?: TransactionEngine;
+
+  constructor(options?: ISessionEngineOptions) {
+    this.sessionTimeoutMs = options?.sessionTimeoutMs ?? 30 * 60 * 1000; // 30 minutes default
+    const cleanupIntervalMs = options?.cleanupIntervalMs ?? 60 * 1000; // 1 minute default
+
+    // Start cleanup interval
+    this.cleanupInterval = setInterval(() => {
+      this.cleanupExpiredSessions();
+    }, cleanupIntervalMs);
+  }
+
+  /**
+   * Set the transaction engine to use for auto-abort
+   */
+  setTransactionEngine(engine: TransactionEngine): void {
+    this.transactionEngine = engine;
+  }
+
+  /**
+   * Start a new session
+   */
+  startSession(sessionId?: string, metadata?: Record<string, any>): ISession {
+    const id = sessionId ?? new plugins.bson.UUID().toHexString();
+    const now = Date.now();
+
+    const session: ISession = {
+      id,
+      createdAt: now,
+      lastActivityAt: now,
+      inTransaction: false,
+      metadata,
+    };
+
+    this.sessions.set(id, session);
+    return session;
+  }
+
+  /**
+   * Get a session by ID
+   */
+  getSession(sessionId: string): ISession | undefined {
+    const session = this.sessions.get(sessionId);
+    if (session && this.isSessionExpired(session)) {
+      // Session expired, clean it up
+      this.endSession(sessionId);
+      return undefined;
+    }
+    return session;
+  }
+
+  /**
+   * Touch a session to update last activity time
+   */
+  touchSession(sessionId: string): boolean {
+    const session = this.sessions.get(sessionId);
+    if (!session) return false;
+
+    if (this.isSessionExpired(session)) {
+      this.endSession(sessionId);
+      return false;
+    }
+
+    session.lastActivityAt = Date.now();
+    return true;
+  }
+
+  /**
+   * End a session explicitly
+   * This will also abort any active transaction
+   */
+  async endSession(sessionId: string): Promise<boolean> {
+    const session = this.sessions.get(sessionId);
+    if (!session) return false;
+
+    // If session has an active transaction, abort it
+    if (session.inTransaction && session.txnId && this.transactionEngine) {
+      try {
+        await this.transactionEngine.abortTransaction(session.txnId);
+      } catch (e) {
+        // Ignore abort errors during cleanup
+      }
+    }
+
+    this.sessions.delete(sessionId);
+    return true;
+  }
+
+  /**
+   * Start a transaction in a session
+   */
+  startTransaction(sessionId: string, txnId: string, txnNumber?: number): boolean {
+    const session = this.sessions.get(sessionId);
+    if (!session) return false;
+
+    if (this.isSessionExpired(session)) {
+      this.endSession(sessionId);
+      return false;
+    }
+
+    session.txnId = txnId;
+    session.txnNumber = txnNumber;
+    session.inTransaction = true;
+    session.lastActivityAt = Date.now();
+
+    return true;
+  }
+
+  /**
+   * End a transaction in a session (commit or abort)
+   */
+  endTransaction(sessionId: string): boolean {
+    const session = this.sessions.get(sessionId);
+    if (!session) return false;
+
+    session.txnId = undefined;
+    session.txnNumber = undefined;
+    session.inTransaction = false;
+    session.lastActivityAt = Date.now();
+
+    return true;
+  }
+
+  /**
+   * Get transaction ID for a session
+   */
+  getTransactionId(sessionId: string): string | undefined {
+    const session = this.sessions.get(sessionId);
+    return session?.txnId;
+  }
+
+  /**
+   * Check if session is in a transaction
+   */
+  isInTransaction(sessionId: string): boolean {
+    const session = this.sessions.get(sessionId);
+    return session?.inTransaction ?? false;
+  }
+
+  /**
+   * Check if a session is expired
+   */
+  isSessionExpired(session: ISession): boolean {
+    return Date.now() - session.lastActivityAt > this.sessionTimeoutMs;
+  }
+
+  /**
+   * Cleanup expired sessions
+   * This is called periodically by the cleanup interval
+   */
+  private async cleanupExpiredSessions(): Promise<void> {
+    const expiredSessions: string[] = [];
+
+    for (const [id, session] of this.sessions) {
+      if (this.isSessionExpired(session)) {
+        expiredSessions.push(id);
+      }
+    }
+
+    // End all expired sessions (this will also abort their transactions)
+    for (const sessionId of expiredSessions) {
+      await this.endSession(sessionId);
+    }
+  }
+
+  /**
+   * Get all active sessions
+   */
+  listSessions(): ISession[] {
+    const activeSessions: ISession[] = [];
+    for (const session of this.sessions.values()) {
+      if (!this.isSessionExpired(session)) {
+        activeSessions.push(session);
+      }
+    }
+    return activeSessions;
+  }
+
+  /**
+   * Get session count
+   */
+  getSessionCount(): number {
+    return this.sessions.size;
+  }
+
+  /**
+   * Get sessions with active transactions
+   */
+  getSessionsWithTransactions(): ISession[] {
+    return this.listSessions().filter(s => s.inTransaction);
+  }
+
+  /**
+   * Refresh session timeout
+   */
+  refreshSession(sessionId: string): boolean {
+    return this.touchSession(sessionId);
+  }
+
+  /**
+   * Close the session engine and cleanup
+   */
+  close(): void {
+    if (this.cleanupInterval) {
+      clearInterval(this.cleanupInterval);
+      this.cleanupInterval = undefined;
+    }
+
+    // Clear all sessions
+    this.sessions.clear();
+  }
+
+  /**
+   * Get or create a session for a given session ID
+   * Useful for handling MongoDB driver session requests
+   */
+  getOrCreateSession(sessionId: string): ISession {
+    let session = this.getSession(sessionId);
+    if (!session) {
+      session = this.startSession(sessionId);
+    } else {
+      this.touchSession(sessionId);
+    }
+    return session;
+  }
+
+  /**
+   * Extract session ID from MongoDB lsid (logical session ID)
+   */
+  static extractSessionId(lsid: any): string | undefined {
+    if (!lsid) return undefined;
+
+    // MongoDB session ID format: { id: UUID }
+    if (lsid.id) {
+      if (lsid.id instanceof plugins.bson.UUID) {
+        return lsid.id.toHexString();
+      }
+      if (typeof lsid.id === 'string') {
+        return lsid.id;
+      }
+      if (lsid.id.$binary?.base64) {
+        // Binary UUID format
+        return Buffer.from(lsid.id.$binary.base64, 'base64').toString('hex');
+      }
+    }
+
+    return undefined;
+  }
+}

ts/ts_tsmdb/engine/TransactionEngine.ts

@@ -1,7 +1,7 @@
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
 import type { Document, IStoredDocument, ITransactionOptions } from '../types/interfaces.js';
-import { CongoTransactionError, CongoWriteConflictError } from '../errors/CongoErrors.js';
+import { TsmdbTransactionError, TsmdbWriteConflictError } from '../errors/TsmdbErrors.js';
 
 /**
  * Transaction state
@@ -70,7 +70,7 @@ export class TransactionEngine {
   async getSnapshot(txnId: string, dbName: string, collName: string): Promise<IStoredDocument[]> {
     const txn = this.transactions.get(txnId);
     if (!txn || txn.status !== 'active') {
-      throw new CongoTransactionError('Transaction is not active');
+      throw new TsmdbTransactionError('Transaction is not active');
     }
 
     const ns = `${dbName}.${collName}`;
@@ -148,7 +148,7 @@ export class TransactionEngine {
   recordInsert(txnId: string, dbName: string, collName: string, doc: IStoredDocument): void {
     const txn = this.transactions.get(txnId);
     if (!txn || txn.status !== 'active') {
-      throw new CongoTransactionError('Transaction is not active');
+      throw new TsmdbTransactionError('Transaction is not active');
     }
 
     const ns = `${dbName}.${collName}`;
@@ -174,7 +174,7 @@ export class TransactionEngine {
   ): void {
     const txn = this.transactions.get(txnId);
     if (!txn || txn.status !== 'active') {
-      throw new CongoTransactionError('Transaction is not active');
+      throw new TsmdbTransactionError('Transaction is not active');
     }
 
     const ns = `${dbName}.${collName}`;
@@ -203,7 +203,7 @@ export class TransactionEngine {
   recordDelete(txnId: string, dbName: string, collName: string, doc: IStoredDocument): void {
     const txn = this.transactions.get(txnId);
     if (!txn || txn.status !== 'active') {
-      throw new CongoTransactionError('Transaction is not active');
+      throw new TsmdbTransactionError('Transaction is not active');
     }
 
     const ns = `${dbName}.${collName}`;
@@ -231,10 +231,10 @@ export class TransactionEngine {
   async commitTransaction(txnId: string): Promise<void> {
     const txn = this.transactions.get(txnId);
     if (!txn) {
-      throw new CongoTransactionError('Transaction not found');
+      throw new TsmdbTransactionError('Transaction not found');
     }
     if (txn.status !== 'active') {
-      throw new CongoTransactionError(`Cannot commit transaction in state: ${txn.status}`);
+      throw new TsmdbTransactionError(`Cannot commit transaction in state: ${txn.status}`);
     }
 
     // Check for write conflicts
@@ -245,7 +245,7 @@ export class TransactionEngine {
       const hasConflicts = await this.storage.hasConflicts(dbName, collName, ids, txn.startTime);
       if (hasConflicts) {
         txn.status = 'aborted';
-        throw new CongoWriteConflictError();
+        throw new TsmdbWriteConflictError();
       }
     }
 
@@ -281,7 +281,7 @@ export class TransactionEngine {
   async abortTransaction(txnId: string): Promise<void> {
     const txn = this.transactions.get(txnId);
     if (!txn) {
-      throw new CongoTransactionError('Transaction not found');
+      throw new TsmdbTransactionError('Transaction not found');
     }
     if (txn.status !== 'active') {
       // Already committed or aborted, just return
@@ -336,7 +336,7 @@ export class TransactionEngine {
         await this.abortTransaction(txnId);
         this.endTransaction(txnId);
 
-        if (error instanceof CongoWriteConflictError && attempt < maxRetries - 1) {
+        if (error instanceof TsmdbWriteConflictError && attempt < maxRetries - 1) {
           // Retry on write conflict
           lastError = error;
           continue;
@@ -346,6 +346,6 @@ export class TransactionEngine {
       }
     }
 
-    throw lastError || new CongoTransactionError('Transaction failed after max retries');
+    throw lastError || new TsmdbTransactionError('Transaction failed after max retries');
   }
 }

ts/ts_tsmdb/engine/UpdateEngine.ts

@@ -1,4 +1,4 @@
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 import type { Document, IStoredDocument } from '../types/interfaces.js';
 import { QueryEngine } from './QueryEngine.js';
 

ts/ts_tsmdb/errors/TsmdbErrors.ts

@@ -1,14 +1,14 @@
 /**
- * Base error class for all CongoDB errors
+ * Base error class for all TsmDB errors
  * Mirrors MongoDB driver error hierarchy
  */
-export class CongoError extends Error {
+export class TsmdbError extends Error {
   public code?: number;
   public codeName?: string;
 
   constructor(message: string, code?: number, codeName?: string) {
     super(message);
-    this.name = 'CongoError';
+    this.name = 'TsmdbError';
     this.code = code;
     this.codeName = codeName;
     Object.setPrototypeOf(this, new.target.prototype);
@@ -18,33 +18,33 @@ export class CongoError extends Error {
 /**
  * Error thrown during connection issues
  */
-export class CongoConnectionError extends CongoError {
+export class TsmdbConnectionError extends TsmdbError {
   constructor(message: string) {
     super(message);
-    this.name = 'CongoConnectionError';
+    this.name = 'TsmdbConnectionError';
   }
 }
 
 /**
  * Error thrown when an operation times out
  */
-export class CongoTimeoutError extends CongoError {
+export class TsmdbTimeoutError extends TsmdbError {
   constructor(message: string) {
     super(message, 50, 'MaxTimeMSExpired');
-    this.name = 'CongoTimeoutError';
+    this.name = 'TsmdbTimeoutError';
   }
 }
 
 /**
  * Error thrown during write operations
  */
-export class CongoWriteError extends CongoError {
+export class TsmdbWriteError extends TsmdbError {
   public writeErrors?: IWriteError[];
   public result?: any;
 
   constructor(message: string, code?: number, writeErrors?: IWriteError[]) {
     super(message, code);
-    this.name = 'CongoWriteError';
+    this.name = 'TsmdbWriteError';
     this.writeErrors = writeErrors;
   }
 }
@@ -52,13 +52,13 @@ export class CongoWriteError extends CongoError {
 /**
  * Error thrown for duplicate key violations
  */
-export class CongoDuplicateKeyError extends CongoWriteError {
+export class TsmdbDuplicateKeyError extends TsmdbWriteError {
   public keyPattern?: Record<string, 1>;
   public keyValue?: Record<string, any>;
 
   constructor(message: string, keyPattern?: Record<string, 1>, keyValue?: Record<string, any>) {
     super(message, 11000);
-    this.name = 'CongoDuplicateKeyError';
+    this.name = 'TsmdbDuplicateKeyError';
     this.codeName = 'DuplicateKey';
     this.keyPattern = keyPattern;
     this.keyValue = keyValue;
@@ -68,13 +68,13 @@ export class CongoDuplicateKeyError extends CongoWriteError {
 /**
  * Error thrown for bulk write failures
  */
-export class CongoBulkWriteError extends CongoError {
+export class TsmdbBulkWriteError extends TsmdbError {
   public writeErrors: IWriteError[];
   public result: any;
 
   constructor(message: string, writeErrors: IWriteError[], result: any) {
     super(message, 65);
-    this.name = 'CongoBulkWriteError';
+    this.name = 'TsmdbBulkWriteError';
     this.writeErrors = writeErrors;
     this.result = result;
   }
@@ -83,20 +83,20 @@ export class CongoBulkWriteError extends CongoError {
 /**
  * Error thrown during transaction operations
  */
-export class CongoTransactionError extends CongoError {
+export class TsmdbTransactionError extends TsmdbError {
   constructor(message: string, code?: number) {
     super(message, code);
-    this.name = 'CongoTransactionError';
+    this.name = 'TsmdbTransactionError';
   }
 }
 
 /**
  * Error thrown when a transaction is aborted due to conflict
  */
-export class CongoWriteConflictError extends CongoTransactionError {
+export class TsmdbWriteConflictError extends TsmdbTransactionError {
   constructor(message: string = 'Write conflict during transaction') {
     super(message, 112);
-    this.name = 'CongoWriteConflictError';
+    this.name = 'TsmdbWriteConflictError';
     this.codeName = 'WriteConflict';
   }
 }
@@ -104,20 +104,20 @@ export class CongoWriteConflictError extends CongoTransactionError {
 /**
  * Error thrown for invalid arguments
  */
-export class CongoArgumentError extends CongoError {
+export class TsmdbArgumentError extends TsmdbError {
   constructor(message: string) {
     super(message);
-    this.name = 'CongoArgumentError';
+    this.name = 'TsmdbArgumentError';
   }
 }
 
 /**
  * Error thrown when an operation is not supported
  */
-export class CongoNotSupportedError extends CongoError {
+export class TsmdbNotSupportedError extends TsmdbError {
   constructor(message: string) {
     super(message, 115);
-    this.name = 'CongoNotSupportedError';
+    this.name = 'TsmdbNotSupportedError';
     this.codeName = 'CommandNotSupported';
   }
 }
@@ -125,20 +125,20 @@ export class CongoNotSupportedError extends CongoError {
 /**
  * Error thrown when cursor is exhausted or closed
  */
-export class CongoCursorError extends CongoError {
+export class TsmdbCursorError extends TsmdbError {
   constructor(message: string) {
     super(message);
-    this.name = 'CongoCursorError';
+    this.name = 'TsmdbCursorError';
   }
 }
 
 /**
  * Error thrown when a namespace (database.collection) is invalid
  */
-export class CongoNamespaceError extends CongoError {
+export class TsmdbNamespaceError extends TsmdbError {
   constructor(message: string) {
     super(message, 73);
-    this.name = 'CongoNamespaceError';
+    this.name = 'TsmdbNamespaceError';
     this.codeName = 'InvalidNamespace';
   }
 }
@@ -146,10 +146,10 @@ export class CongoNamespaceError extends CongoError {
 /**
  * Error thrown when an index operation fails
  */
-export class CongoIndexError extends CongoError {
+export class TsmdbIndexError extends TsmdbError {
   constructor(message: string, code?: number) {
     super(message, code || 86);
-    this.name = 'CongoIndexError';
+    this.name = 'TsmdbIndexError';
   }
 }
 
@@ -164,18 +164,18 @@ export interface IWriteError {
 }
 
 /**
- * Convert any error to a CongoError
+ * Convert any error to a TsmdbError
  */
-export function toCongoError(error: any): CongoError {
-  if (error instanceof CongoError) {
+export function toTsmdbError(error: any): TsmdbError {
+  if (error instanceof TsmdbError) {
     return error;
   }
-  const congoError = new CongoError(error.message || String(error));
+  const tsmdbError = new TsmdbError(error.message || String(error));
   if (error.code) {
-    congoError.code = error.code;
+    tsmdbError.code = error.code;
   }
   if (error.codeName) {
-    congoError.codeName = error.codeName;
+    tsmdbError.codeName = error.codeName;
   }
-  return congoError;
+  return tsmdbError;
 }

ts/ts_tsmdb/index.ts

@@ -1,8 +1,8 @@
-// CongoDB - MongoDB Wire Protocol compatible in-memory database server
-// Use the official MongoDB driver to connect to CongoServer
+// TsmDB - MongoDB Wire Protocol compatible in-memory database server
+// Use the official MongoDB driver to connect to TsmdbServer
 
 // Re-export plugins for external use
-import * as plugins from './congodb.plugins.js';
+import * as plugins from './plugins.js';
 export { plugins };
 
 // Export BSON types for convenience
@@ -12,13 +12,15 @@ export { ObjectId, Binary, Timestamp, Long, Decimal128, UUID } from 'bson';
 export * from './types/interfaces.js';
 
 // Export errors
-export * from './errors/CongoErrors.js';
+export * from './errors/TsmdbErrors.js';
 
 // Export storage adapters
 export type { IStorageAdapter } from './storage/IStorageAdapter.js';
 export { MemoryStorageAdapter } from './storage/MemoryStorageAdapter.js';
 export { FileStorageAdapter } from './storage/FileStorageAdapter.js';
 export { OpLog } from './storage/OpLog.js';
+export { WAL } from './storage/WAL.js';
+export type { IWalEntry, TWalOperation } from './storage/WAL.js';
 
 // Export engines
 export { QueryEngine } from './engine/QueryEngine.js';
@@ -26,12 +28,19 @@ export { UpdateEngine } from './engine/UpdateEngine.js';
 export { AggregationEngine } from './engine/AggregationEngine.js';
 export { IndexEngine } from './engine/IndexEngine.js';
 export { TransactionEngine } from './engine/TransactionEngine.js';
+export { QueryPlanner } from './engine/QueryPlanner.js';
+export type { IQueryPlan, TQueryPlanType } from './engine/QueryPlanner.js';
+export { SessionEngine } from './engine/SessionEngine.js';
+export type { ISession, ISessionEngineOptions } from './engine/SessionEngine.js';
 
-// Export server (the main entry point for using CongoDB)
-export { CongoServer } from './server/CongoServer.js';
-export type { ICongoServerOptions } from './server/CongoServer.js';
+// Export server (the main entry point for using TsmDB)
+export { TsmdbServer } from './server/TsmdbServer.js';
+export type { ITsmdbServerOptions } from './server/TsmdbServer.js';
 
 // Export wire protocol utilities (for advanced usage)
 export { WireProtocol } from './server/WireProtocol.js';
 export { CommandRouter } from './server/CommandRouter.js';
 export type { ICommandHandler, IHandlerContext, ICursorState } from './server/CommandRouter.js';
+
+// Export utilities
+export * from './utils/checksum.js';

ts/ts_tsmdb/server/CommandRouter.ts

@@ -1,7 +1,10 @@
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
 import type { IParsedCommand } from './WireProtocol.js';
-import type { CongoServer } from './CongoServer.js';
+import type { TsmdbServer } from './TsmdbServer.js';
+import { IndexEngine } from '../engine/IndexEngine.js';
+import { TransactionEngine } from '../engine/TransactionEngine.js';
+import { SessionEngine } from '../engine/SessionEngine.js';
 
 // Import handlers
 import { HelloHandler } from './handlers/HelloHandler.js';
@@ -18,10 +21,20 @@ import { AdminHandler } from './handlers/AdminHandler.js';
  */
 export interface IHandlerContext {
   storage: IStorageAdapter;
-  server: CongoServer;
+  server: TsmdbServer;
   database: string;
   command: plugins.bson.Document;
   documentSequences?: Map<string, plugins.bson.Document[]>;
+  /** Get or create an IndexEngine for a collection */
+  getIndexEngine: (collName: string) => IndexEngine;
+  /** Transaction engine instance */
+  transactionEngine: TransactionEngine;
+  /** Current transaction ID (if in a transaction) */
+  txnId?: string;
+  /** Session ID (from lsid) */
+  sessionId?: string;
+  /** Session engine instance */
+  sessionEngine: SessionEngine;
 }
 
 /**
@@ -36,19 +49,61 @@ export interface ICommandHandler {
  */
 export class CommandRouter {
   private storage: IStorageAdapter;
-  private server: CongoServer;
+  private server: TsmdbServer;
   private handlers: Map<string, ICommandHandler> = new Map();
 
   // Cursor state for getMore operations
   private cursors: Map<bigint, ICursorState> = new Map();
   private cursorIdCounter: bigint = BigInt(1);
 
-  constructor(storage: IStorageAdapter, server: CongoServer) {
+  // Index engine cache: db.collection -> IndexEngine
+  private indexEngines: Map<string, IndexEngine> = new Map();
+
+  // Transaction engine (shared across all handlers)
+  private transactionEngine: TransactionEngine;
+
+  // Session engine (shared across all handlers)
+  private sessionEngine: SessionEngine;
+
+  constructor(storage: IStorageAdapter, server: TsmdbServer) {
     this.storage = storage;
     this.server = server;
+    this.transactionEngine = new TransactionEngine(storage);
+    this.sessionEngine = new SessionEngine();
+    // Link session engine to transaction engine for auto-abort on session expiry
+    this.sessionEngine.setTransactionEngine(this.transactionEngine);
     this.registerHandlers();
   }
 
+  /**
+   * Get or create an IndexEngine for a database.collection
+   */
+  getIndexEngine(dbName: string, collName: string): IndexEngine {
+    const key = `${dbName}.${collName}`;
+    let engine = this.indexEngines.get(key);
+    if (!engine) {
+      engine = new IndexEngine(dbName, collName, this.storage);
+      this.indexEngines.set(key, engine);
+    }
+    return engine;
+  }
+
+  /**
+   * Clear index engine cache for a collection (used when collection is dropped)
+   */
+  clearIndexEngineCache(dbName: string, collName?: string): void {
+    if (collName) {
+      this.indexEngines.delete(`${dbName}.${collName}`);
+    } else {
+      // Clear all engines for the database
+      for (const key of this.indexEngines.keys()) {
+        if (key.startsWith(`${dbName}.`)) {
+          this.indexEngines.delete(key);
+        }
+      }
+    }
+  }
+
   /**
    * Register all command handlers
    */
@@ -120,6 +175,29 @@ export class CommandRouter {
   async route(parsedCommand: IParsedCommand): Promise<plugins.bson.Document> {
     const { commandName, command, database, documentSequences } = parsedCommand;
 
+    // Extract session ID from lsid using SessionEngine helper
+    let sessionId = SessionEngine.extractSessionId(command.lsid);
+    let txnId: string | undefined;
+
+    // If we have a session ID, register/touch the session
+    if (sessionId) {
+      this.sessionEngine.getOrCreateSession(sessionId);
+    }
+
+    // Check if this starts a new transaction
+    if (command.startTransaction && sessionId) {
+      txnId = this.transactionEngine.startTransaction(sessionId);
+      this.sessionEngine.startTransaction(sessionId, txnId, command.txnNumber);
+    } else if (sessionId && this.sessionEngine.isInTransaction(sessionId)) {
+      // Continue existing transaction
+      txnId = this.sessionEngine.getTransactionId(sessionId);
+      // Verify transaction is still active
+      if (txnId && !this.transactionEngine.isActive(txnId)) {
+        this.sessionEngine.endTransaction(sessionId);
+        txnId = undefined;
+      }
+    }
+
     // Create handler context
     const context: IHandlerContext = {
       storage: this.storage,
@@ -127,6 +205,11 @@ export class CommandRouter {
       database,
       command,
       documentSequences,
+      getIndexEngine: (collName: string) => this.getIndexEngine(database, collName),
+      transactionEngine: this.transactionEngine,
+      sessionEngine: this.sessionEngine,
+      txnId,
+      sessionId,
     };
 
     // Find handler
@@ -164,6 +247,32 @@ export class CommandRouter {
       };
     }
   }
+
+  /**
+   * Close the command router and cleanup resources
+   */
+  close(): void {
+    // Close session engine (stops cleanup interval, clears sessions)
+    this.sessionEngine.close();
+    // Clear cursors
+    this.cursors.clear();
+    // Clear index engine cache
+    this.indexEngines.clear();
+  }
+
+  /**
+   * Get session engine (for administrative purposes)
+   */
+  getSessionEngine(): SessionEngine {
+    return this.sessionEngine;
+  }
+
+  /**
+   * Get transaction engine (for administrative purposes)
+   */
+  getTransactionEngine(): TransactionEngine {
+    return this.transactionEngine;
+  }
 }
 
 /**

ts/ts_tsmdb/server/TsmdbServer.ts

@@ -1,5 +1,5 @@
 import * as net from 'net';
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 import { WireProtocol, OP_QUERY } from './WireProtocol.js';
 import { CommandRouter } from './CommandRouter.js';
 import { MemoryStorageAdapter } from '../storage/MemoryStorageAdapter.js';
@@ -9,7 +9,7 @@ import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
 /**
  * Server configuration options
  */
-export interface ICongoServerOptions {
+export interface ITsmdbServerOptions {
   /** Port to listen on (default: 27017) */
   port?: number;
   /** Host to bind to (default: 127.0.0.1) */
@@ -36,25 +36,25 @@ interface IConnectionState {
 }
 
 /**
- * CongoServer - MongoDB Wire Protocol compatible server
+ * TsmdbServer - MongoDB Wire Protocol compatible server
  *
  * This server implements the MongoDB wire protocol (OP_MSG) to allow
  * official MongoDB drivers to connect and perform operations.
  *
  * @example
  * ```typescript
- * import { CongoServer } from '@push.rocks/smartmongo/congodb';
+ * import { TsmdbServer } from '@push.rocks/smartmongo/tsmdb';
  * import { MongoClient } from 'mongodb';
  *
- * const server = new CongoServer({ port: 27017 });
+ * const server = new TsmdbServer({ port: 27017 });
  * await server.start();
  *
  * const client = new MongoClient('mongodb://127.0.0.1:27017');
  * await client.connect();
  * ```
  */
-export class CongoServer {
-  private options: Required<ICongoServerOptions>;
+export class TsmdbServer {
+  private options: Required<ITsmdbServerOptions>;
   private server: net.Server | null = null;
   private storage: IStorageAdapter;
   private commandRouter: CommandRouter;
@@ -63,7 +63,7 @@ export class CongoServer {
   private isRunning = false;
   private startTime: Date = new Date();
 
-  constructor(options: ICongoServerOptions = {}) {
+  constructor(options: ITsmdbServerOptions = {}) {
     this.options = {
       port: options.port ?? 27017,
       host: options.host ?? '127.0.0.1',
@@ -154,6 +154,9 @@ export class CongoServer {
     }
     this.connections.clear();
 
+    // Close command router (cleans up session engine, cursors, etc.)
+    this.commandRouter.close();
+
     // Close storage
     await this.storage.close();
 

ts/ts_tsmdb/server/WireProtocol.ts

@@ -1,4 +1,4 @@
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 
 /**
  * MongoDB Wire Protocol Implementation

ts/ts_tsmdb/server/handlers/AdminHandler.ts

@@ -1,5 +1,6 @@
-import * as plugins from '../../congodb.plugins.js';
+import * as plugins from '../../plugins.js';
 import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+import { SessionEngine } from '../../engine/SessionEngine.js';
 
 /**
  * AdminHandler - Handles administrative commands
@@ -237,16 +238,18 @@ export class AdminHandler implements ICommandHandler {
    * Handle serverStatus command
    */
   private async handleServerStatus(context: IHandlerContext): Promise<plugins.bson.Document> {
-    const { server } = context;
+    const { server, sessionEngine } = context;
 
     const uptime = server.getUptime();
     const connections = server.getConnectionCount();
+    const sessions = sessionEngine.listSessions();
+    const sessionsWithTxn = sessionEngine.getSessionsWithTransactions();
 
     return {
       ok: 1,
       host: `${server.host}:${server.port}`,
       version: '7.0.0',
-      process: 'congodb',
+      process: 'tsmdb',
       pid: process.pid,
       uptime,
       uptimeMillis: uptime * 1000,
@@ -263,13 +266,33 @@ export class AdminHandler implements ICommandHandler {
         totalCreated: connections,
         active: connections,
       },
+      logicalSessionRecordCache: {
+        activeSessionsCount: sessions.length,
+        sessionsCollectionJobCount: 0,
+        lastSessionsCollectionJobDurationMillis: 0,
+        lastSessionsCollectionJobTimestamp: new Date(),
+        transactionReaperJobCount: 0,
+        lastTransactionReaperJobDurationMillis: 0,
+        lastTransactionReaperJobTimestamp: new Date(),
+      },
+      transactions: {
+        retriedCommandsCount: 0,
+        retriedStatementsCount: 0,
+        transactionsCollectionWriteCount: 0,
+        currentActive: sessionsWithTxn.length,
+        currentInactive: 0,
+        currentOpen: sessionsWithTxn.length,
+        totalStarted: sessionsWithTxn.length,
+        totalCommitted: 0,
+        totalAborted: 0,
+      },
       network: {
         bytesIn: 0,
         bytesOut: 0,
         numRequests: 0,
       },
       storageEngine: {
-        name: 'congodb',
+        name: 'tsmdb',
         supportsCommittedReads: true,
         persistent: false,
       },
@@ -283,7 +306,7 @@ export class AdminHandler implements ICommandHandler {
     return {
       ok: 1,
       version: '7.0.0',
-      gitVersion: 'congodb',
+      gitVersion: 'tsmdb',
       modules: [],
       allocator: 'system',
       javascriptEngine: 'none',
@@ -294,7 +317,7 @@ export class AdminHandler implements ICommandHandler {
         compiled: 'disabled',
       },
       buildEnvironment: {
-        distmod: 'congodb',
+        distmod: 'tsmdb',
         distarch: process.arch,
         cc: '',
         ccflags: '',
@@ -307,7 +330,7 @@ export class AdminHandler implements ICommandHandler {
       bits: 64,
       debug: false,
       maxBsonObjectSize: 16777216,
-      storageEngines: ['congodb'],
+      storageEngines: ['tsmdb'],
     };
   }
 
@@ -409,6 +432,17 @@ export class AdminHandler implements ICommandHandler {
    * Handle endSessions command
    */
   private async handleEndSessions(context: IHandlerContext): Promise<plugins.bson.Document> {
+    const { command, sessionEngine } = context;
+
+    // End each session in the array
+    const sessions = command.endSessions || [];
+    for (const sessionSpec of sessions) {
+      const sessionId = SessionEngine.extractSessionId(sessionSpec);
+      if (sessionId) {
+        await sessionEngine.endSession(sessionId);
+      }
+    }
+
     return { ok: 1 };
   }
 
@@ -416,16 +450,87 @@ export class AdminHandler implements ICommandHandler {
    * Handle abortTransaction command
    */
   private async handleAbortTransaction(context: IHandlerContext): Promise<plugins.bson.Document> {
-    // Transactions are not fully supported, but acknowledge the command
-    return { ok: 1 };
+    const { transactionEngine, sessionEngine, txnId, sessionId } = context;
+
+    if (!txnId) {
+      return {
+        ok: 0,
+        errmsg: 'No transaction started',
+        code: 251,
+        codeName: 'NoSuchTransaction',
+      };
+    }
+
+    try {
+      await transactionEngine.abortTransaction(txnId);
+      transactionEngine.endTransaction(txnId);
+      // Update session state
+      if (sessionId) {
+        sessionEngine.endTransaction(sessionId);
+      }
+      return { ok: 1 };
+    } catch (error: any) {
+      return {
+        ok: 0,
+        errmsg: error.message || 'Abort transaction failed',
+        code: error.code || 1,
+        codeName: error.codeName || 'UnknownError',
+      };
+    }
   }
 
   /**
    * Handle commitTransaction command
    */
   private async handleCommitTransaction(context: IHandlerContext): Promise<plugins.bson.Document> {
-    // Transactions are not fully supported, but acknowledge the command
-    return { ok: 1 };
+    const { transactionEngine, sessionEngine, txnId, sessionId } = context;
+
+    if (!txnId) {
+      return {
+        ok: 0,
+        errmsg: 'No transaction started',
+        code: 251,
+        codeName: 'NoSuchTransaction',
+      };
+    }
+
+    try {
+      await transactionEngine.commitTransaction(txnId);
+      transactionEngine.endTransaction(txnId);
+      // Update session state
+      if (sessionId) {
+        sessionEngine.endTransaction(sessionId);
+      }
+      return { ok: 1 };
+    } catch (error: any) {
+      // If commit fails, transaction should be aborted
+      try {
+        await transactionEngine.abortTransaction(txnId);
+        transactionEngine.endTransaction(txnId);
+        if (sessionId) {
+          sessionEngine.endTransaction(sessionId);
+        }
+      } catch {
+        // Ignore abort errors
+      }
+
+      if (error.code === 112) {
+        // Write conflict
+        return {
+          ok: 0,
+          errmsg: error.message || 'Write conflict during commit',
+          code: 112,
+          codeName: 'WriteConflict',
+        };
+      }
+
+      return {
+        ok: 0,
+        errmsg: error.message || 'Commit transaction failed',
+        code: error.code || 1,
+        codeName: error.codeName || 'UnknownError',
+      };
+    }
   }
 
   /**

ts/ts_tsmdb/server/handlers/AggregateHandler.ts

@@ -1,4 +1,4 @@
-import * as plugins from '../../congodb.plugins.js';
+import * as plugins from '../../plugins.js';
 import type { ICommandHandler, IHandlerContext, ICursorState } from '../CommandRouter.js';
 import { AggregationEngine } from '../../engine/AggregationEngine.js';
 

ts/ts_tsmdb/server/handlers/DeleteHandler.ts

@@ -1,5 +1,6 @@
-import * as plugins from '../../congodb.plugins.js';
+import * as plugins from '../../plugins.js';
 import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+import type { IStoredDocument } from '../../types/interfaces.js';
 import { QueryEngine } from '../../engine/QueryEngine.js';
 
 /**
@@ -47,6 +48,8 @@ export class DeleteHandler implements ICommandHandler {
       return { ok: 1, n: 0 };
     }
 
+    const indexEngine = context.getIndexEngine(collection);
+
     for (let i = 0; i < deletes.length; i++) {
       const deleteSpec = deletes[i];
       const filter = deleteSpec.q || deleteSpec.filter || {};
@@ -56,8 +59,15 @@ export class DeleteHandler implements ICommandHandler {
       const deleteAll = limit === 0;
 
       try {
-        // Get all documents
-        const documents = await storage.findAll(database, collection);
+        // Try to use index-accelerated query
+        const candidateIds = await indexEngine.findCandidateIds(filter);
+
+        let documents: IStoredDocument[];
+        if (candidateIds !== null) {
+          documents = await storage.findByIds(database, collection, candidateIds);
+        } else {
+          documents = await storage.findAll(database, collection);
+        }
 
         // Apply filter
         const matchingDocs = QueryEngine.filter(documents, filter);
@@ -69,6 +79,11 @@ export class DeleteHandler implements ICommandHandler {
         // Determine which documents to delete
         const docsToDelete = deleteAll ? matchingDocs : matchingDocs.slice(0, 1);
 
+        // Update indexes for deleted documents
+        for (const doc of docsToDelete) {
+          await indexEngine.onDelete(doc as any);
+        }
+
         // Delete the documents
         const idsToDelete = docsToDelete.map(doc => doc._id);
         const deleted = await storage.deleteByIds(database, collection, idsToDelete);

ts/ts_tsmdb/server/handlers/FindHandler.ts

@@ -1,5 +1,6 @@
-import * as plugins from '../../congodb.plugins.js';
+import * as plugins from '../../plugins.js';
 import type { ICommandHandler, IHandlerContext, ICursorState } from '../CommandRouter.js';
+import type { IStoredDocument } from '../../types/interfaces.js';
 import { QueryEngine } from '../../engine/QueryEngine.js';
 
 /**
@@ -45,7 +46,7 @@ export class FindHandler implements ICommandHandler {
    * Handle find command
    */
   private async handleFind(context: IHandlerContext): Promise<plugins.bson.Document> {
-    const { storage, database, command } = context;
+    const { storage, database, command, getIndexEngine } = context;
 
     const collection = command.find;
     const filter = command.filter || {};
@@ -70,11 +71,22 @@ export class FindHandler implements ICommandHandler {
       };
     }
 
-    // Get all documents
-    let documents = await storage.findAll(database, collection);
+    // Try to use index-accelerated query
+    const indexEngine = getIndexEngine(collection);
+    const candidateIds = await indexEngine.findCandidateIds(filter);
 
-    // Apply filter
-    documents = QueryEngine.filter(documents, filter);
+    let documents: IStoredDocument[];
+    if (candidateIds !== null) {
+      // Index hit - fetch only candidate documents
+      documents = await storage.findByIds(database, collection, candidateIds);
+      // Still apply filter for any conditions the index couldn't fully satisfy
+      documents = QueryEngine.filter(documents, filter);
+    } else {
+      // No suitable index - full collection scan
+      documents = await storage.findAll(database, collection);
+      // Apply filter
+      documents = QueryEngine.filter(documents, filter);
+    }
 
     // Apply sort
     if (sort) {
@@ -233,7 +245,7 @@ export class FindHandler implements ICommandHandler {
    * Handle count command
    */
   private async handleCount(context: IHandlerContext): Promise<plugins.bson.Document> {
-    const { storage, database, command } = context;
+    const { storage, database, command, getIndexEngine } = context;
 
     const collection = command.count;
     const query = command.query || {};
@@ -246,11 +258,20 @@ export class FindHandler implements ICommandHandler {
       return { ok: 1, n: 0 };
     }
 
-    // Get all documents
-    let documents = await storage.findAll(database, collection);
+    // Try to use index-accelerated query
+    const indexEngine = getIndexEngine(collection);
+    const candidateIds = await indexEngine.findCandidateIds(query);
 
-    // Apply filter
-    documents = QueryEngine.filter(documents, query);
+    let documents: IStoredDocument[];
+    if (candidateIds !== null) {
+      // Index hit - fetch only candidate documents
+      documents = await storage.findByIds(database, collection, candidateIds);
+      documents = QueryEngine.filter(documents, query);
+    } else {
+      // No suitable index - full collection scan
+      documents = await storage.findAll(database, collection);
+      documents = QueryEngine.filter(documents, query);
+    }
 
     // Apply skip
     if (skip > 0) {
@@ -269,7 +290,7 @@ export class FindHandler implements ICommandHandler {
    * Handle distinct command
    */
   private async handleDistinct(context: IHandlerContext): Promise<plugins.bson.Document> {
-    const { storage, database, command } = context;
+    const { storage, database, command, getIndexEngine } = context;
 
     const collection = command.distinct;
     const key = command.key;
@@ -290,8 +311,16 @@ export class FindHandler implements ICommandHandler {
       return { ok: 1, values: [] };
     }
 
-    // Get all documents
-    const documents = await storage.findAll(database, collection);
+    // Try to use index-accelerated query
+    const indexEngine = getIndexEngine(collection);
+    const candidateIds = await indexEngine.findCandidateIds(query);
+
+    let documents: IStoredDocument[];
+    if (candidateIds !== null) {
+      documents = await storage.findByIds(database, collection, candidateIds);
+    } else {
+      documents = await storage.findAll(database, collection);
+    }
 
     // Get distinct values
     const values = QueryEngine.distinct(documents, key, query);

ts/ts_tsmdb/server/handlers/HelloHandler.ts

@@ -1,4 +1,4 @@
-import * as plugins from '../../congodb.plugins.js';
+import * as plugins from '../../plugins.js';
 import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
 
 /**

ts/ts_tsmdb/server/handlers/IndexHandler.ts

@@ -1,4 +1,4 @@
-import * as plugins from '../../congodb.plugins.js';
+import * as plugins from '../../plugins.js';
 import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
 import { IndexEngine } from '../../engine/IndexEngine.js';
 

ts/ts_tsmdb/server/handlers/InsertHandler.ts

@@ -1,5 +1,6 @@
-import * as plugins from '../../congodb.plugins.js';
+import * as plugins from '../../plugins.js';
 import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+import type { IStoredDocument } from '../../types/interfaces.js';
 
 /**
  * InsertHandler - Handles insert commands
@@ -42,6 +43,8 @@ export class InsertHandler implements ICommandHandler {
     // Ensure collection exists
     await storage.createCollection(database, collection);
 
+    const indexEngine = context.getIndexEngine(collection);
+
     // Insert documents
     for (let i = 0; i < documents.length; i++) {
       const doc = documents[i];
@@ -52,6 +55,9 @@ export class InsertHandler implements ICommandHandler {
           doc._id = new plugins.bson.ObjectId();
         }
 
+        // Check index constraints before insert (doc now has _id)
+        await indexEngine.onInsert(doc as IStoredDocument);
+
         await storage.insertOne(database, collection, doc);
         insertedCount++;
       } catch (error: any) {

ts/ts_tsmdb/server/handlers/UpdateHandler.ts

@@ -1,5 +1,6 @@
-import * as plugins from '../../congodb.plugins.js';
+import * as plugins from '../../plugins.js';
 import type { ICommandHandler, IHandlerContext } from '../CommandRouter.js';
+import type { IStoredDocument } from '../../types/interfaces.js';
 import { QueryEngine } from '../../engine/QueryEngine.js';
 import { UpdateEngine } from '../../engine/UpdateEngine.js';
 
@@ -69,6 +70,8 @@ export class UpdateHandler implements ICommandHandler {
     // Ensure collection exists
     await storage.createCollection(database, collection);
 
+    const indexEngine = context.getIndexEngine(collection);
+
     for (let i = 0; i < updates.length; i++) {
       const updateSpec = updates[i];
       const filter = updateSpec.q || updateSpec.filter || {};
@@ -78,8 +81,15 @@ export class UpdateHandler implements ICommandHandler {
       const arrayFilters = updateSpec.arrayFilters;
 
       try {
-        // Get all documents
-        let documents = await storage.findAll(database, collection);
+        // Try to use index-accelerated query
+        const candidateIds = await indexEngine.findCandidateIds(filter);
+
+        let documents: IStoredDocument[];
+        if (candidateIds !== null) {
+          documents = await storage.findByIds(database, collection, candidateIds);
+        } else {
+          documents = await storage.findAll(database, collection);
+        }
 
         // Apply filter
         let matchingDocs = QueryEngine.filter(documents, filter);
@@ -99,6 +109,8 @@ export class UpdateHandler implements ICommandHandler {
             Object.assign(updatedDoc, update.$setOnInsert);
           }
 
+          // Update index for the new document
+          await indexEngine.onInsert(updatedDoc);
           await storage.insertOne(database, collection, updatedDoc);
           totalUpserted++;
           upserted.push({ index: i, _id: updatedDoc._id });
@@ -113,6 +125,8 @@ export class UpdateHandler implements ICommandHandler {
             // Check if document actually changed
             const changed = JSON.stringify(doc) !== JSON.stringify(updatedDoc);
             if (changed) {
+              // Update index
+              await indexEngine.onUpdate(doc as any, updatedDoc);
               await storage.updateById(database, collection, doc._id, updatedDoc);
               totalModified++;
             }
@@ -186,8 +200,17 @@ export class UpdateHandler implements ICommandHandler {
     // Ensure collection exists
     await storage.createCollection(database, collection);
 
-    // Get matching documents
-    let documents = await storage.findAll(database, collection);
+    // Try to use index-accelerated query
+    const indexEngine = context.getIndexEngine(collection);
+    const candidateIds = await indexEngine.findCandidateIds(query);
+
+    let documents: IStoredDocument[];
+    if (candidateIds !== null) {
+      documents = await storage.findByIds(database, collection, candidateIds);
+    } else {
+      documents = await storage.findAll(database, collection);
+    }
+
     let matchingDocs = QueryEngine.filter(documents, query);
 
     // Apply sort if specified
@@ -203,6 +226,8 @@ export class UpdateHandler implements ICommandHandler {
         return { ok: 1, value: null };
       }
 
+      // Update index for delete
+      await indexEngine.onDelete(doc as any);
       await storage.deleteById(database, collection, doc._id);
 
       let result = doc;
@@ -231,6 +256,8 @@ export class UpdateHandler implements ICommandHandler {
         // Update existing
         originalDoc = { ...doc };
         resultDoc = UpdateEngine.applyUpdate(doc, update, arrayFilters);
+        // Update index
+        await indexEngine.onUpdate(doc as any, resultDoc as any);
         await storage.updateById(database, collection, doc._id, resultDoc as any);
       } else {
         // Upsert
@@ -243,6 +270,8 @@ export class UpdateHandler implements ICommandHandler {
           Object.assign(resultDoc, update.$setOnInsert);
         }
 
+        // Update index for insert
+        await indexEngine.onInsert(resultDoc as any);
         await storage.insertOne(database, collection, resultDoc);
       }
 

ts/ts_tsmdb/server/index.ts

@@ -1,7 +1,7 @@
 // Server module exports
 
-export { CongoServer } from './CongoServer.js';
-export type { ICongoServerOptions } from './CongoServer.js';
+export { TsmdbServer } from './TsmdbServer.js';
+export type { ITsmdbServerOptions } from './TsmdbServer.js';
 export { WireProtocol } from './WireProtocol.js';
 export { CommandRouter } from './CommandRouter.js';
 export type { ICommandHandler, IHandlerContext, ICursorState } from './CommandRouter.js';

ts/ts_tsmdb/storage/FileStorageAdapter.ts

@@ -1,9 +1,20 @@
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 import type { IStorageAdapter } from './IStorageAdapter.js';
 import type { IStoredDocument, IOpLogEntry, Document } from '../types/interfaces.js';
+import { calculateDocumentChecksum, verifyChecksum } from '../utils/checksum.js';
 
 /**
- * File-based storage adapter for CongoDB
+ * File storage adapter options
+ */
+export interface IFileStorageAdapterOptions {
+  /** Enable checksum verification for data integrity */
+  enableChecksums?: boolean;
+  /** Throw error on checksum mismatch (default: false, just log warning) */
+  strictChecksums?: boolean;
+}
+
+/**
+ * File-based storage adapter for TsmDB
  * Stores data in JSON files on disk for persistence
  */
 export class FileStorageAdapter implements IStorageAdapter {
@@ -11,9 +22,13 @@ export class FileStorageAdapter implements IStorageAdapter {
   private opLogCounter = 0;
   private initialized = false;
   private fs = new plugins.smartfs.SmartFs(new plugins.smartfs.SmartFsProviderNode());
+  private enableChecksums: boolean;
+  private strictChecksums: boolean;
 
-  constructor(basePath: string) {
+  constructor(basePath: string, options?: IFileStorageAdapterOptions) {
     this.basePath = basePath;
+    this.enableChecksums = options?.enableChecksums ?? false;
+    this.strictChecksums = options?.strictChecksums ?? false;
   }
 
   // ============================================================================
@@ -68,6 +83,45 @@ export class FileStorageAdapter implements IStorageAdapter {
     return doc;
   }
 
+  /**
+   * Verify document checksum and handle errors
+   */
+  private verifyDocumentChecksum(doc: any): boolean {
+    if (!this.enableChecksums || !doc._checksum) {
+      return true;
+    }
+
+    const isValid = verifyChecksum(doc);
+    if (!isValid) {
+      const errorMsg = `Checksum mismatch for document ${doc._id}`;
+      if (this.strictChecksums) {
+        throw new Error(errorMsg);
+      } else {
+        console.warn(`WARNING: ${errorMsg}`);
+      }
+    }
+    return isValid;
+  }
+
+  /**
+   * Add checksum to document before storing
+   */
+  private prepareDocumentForStorage(doc: any): any {
+    if (!this.enableChecksums) {
+      return doc;
+    }
+    const checksum = calculateDocumentChecksum(doc);
+    return { ...doc, _checksum: checksum };
+  }
+
+  /**
+   * Remove internal checksum field before returning to user
+   */
+  private cleanDocumentForReturn(doc: any): IStoredDocument {
+    const { _checksum, ...cleanDoc } = doc;
+    return this.restoreObjectIds(cleanDoc);
+  }
+
   // ============================================================================
   // Initialization
   // ============================================================================
@@ -233,7 +287,9 @@ export class FileStorageAdapter implements IStorageAdapter {
       throw new Error(`Duplicate key error: _id ${idStr}`);
     }
 
-    docs.push(storedDoc);
+    // Add checksum if enabled
+    const docToStore = this.prepareDocumentForStorage(storedDoc);
+    docs.push(docToStore);
     await this.writeJsonFile(collPath, docs);
     return storedDoc;
   }
@@ -258,7 +314,9 @@ export class FileStorageAdapter implements IStorageAdapter {
       }
 
       existingIds.add(idStr);
-      docs.push(storedDoc);
+      // Add checksum if enabled
+      const docToStore = this.prepareDocumentForStorage(storedDoc);
+      docs.push(docToStore);
       results.push(storedDoc);
     }
 
@@ -270,10 +328,33 @@ export class FileStorageAdapter implements IStorageAdapter {
     await this.createCollection(dbName, collName);
     const collPath = this.getCollectionPath(dbName, collName);
     const docs = await this.readJsonFile<any[]>(collPath, []);
-    return docs.map(doc => this.restoreObjectIds(doc));
+    return docs.map(doc => {
+      // Verify checksum if enabled
+      this.verifyDocumentChecksum(doc);
+      // Clean and return document without internal checksum field
+      return this.cleanDocumentForReturn(doc);
+    });
+  }
+
+  async findByIds(dbName: string, collName: string, ids: Set<string>): Promise<IStoredDocument[]> {
+    await this.createCollection(dbName, collName);
+    const collPath = this.getCollectionPath(dbName, collName);
+    const docs = await this.readJsonFile<any[]>(collPath, []);
+    const results: IStoredDocument[] = [];
+    for (const doc of docs) {
+      // Verify checksum if enabled
+      this.verifyDocumentChecksum(doc);
+      // Clean and restore document
+      const cleaned = this.cleanDocumentForReturn(doc);
+      if (ids.has(cleaned._id.toHexString())) {
+        results.push(cleaned);
+      }
+    }
+    return results;
   }
 
   async findById(dbName: string, collName: string, id: plugins.bson.ObjectId): Promise<IStoredDocument | null> {
+    // Use findAll which already handles checksum verification
     const docs = await this.findAll(dbName, collName);
     const idStr = id.toHexString();
     return docs.find(d => d._id.toHexString() === idStr) || null;
@@ -291,7 +372,9 @@ export class FileStorageAdapter implements IStorageAdapter {
 
     if (idx === -1) return false;
 
-    docs[idx] = doc;
+    // Add checksum if enabled
+    const docToStore = this.prepareDocumentForStorage(doc);
+    docs[idx] = docToStore;
     await this.writeJsonFile(collPath, docs);
     return true;
   }

ts/ts_tsmdb/storage/IStorageAdapter.ts

@@ -1,8 +1,8 @@
-import type * as plugins from '../congodb.plugins.js';
+import type * as plugins from '../plugins.js';
 import type { IStoredDocument, IOpLogEntry, Document } from '../types/interfaces.js';
 
 /**
- * Storage adapter interface for CongoDB
+ * Storage adapter interface for TsmDB
  * Implementations can provide different storage backends (memory, file, etc.)
  */
 export interface IStorageAdapter {
@@ -90,6 +90,12 @@ export interface IStorageAdapter {
    */
   findAll(dbName: string, collName: string): Promise<IStoredDocument[]>;
 
+  /**
+   * Find documents by a set of _id strings (hex format)
+   * Used for index-accelerated queries
+   */
+  findByIds(dbName: string, collName: string, ids: Set<string>): Promise<IStoredDocument[]>;
+
   /**
    * Find a document by _id
    */

ts/ts_tsmdb/storage/MemoryStorageAdapter.ts

@@ -1,9 +1,9 @@
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 import type { IStorageAdapter } from './IStorageAdapter.js';
 import type { IStoredDocument, IOpLogEntry, Document } from '../types/interfaces.js';
 
 /**
- * In-memory storage adapter for CongoDB
+ * In-memory storage adapter for TsmDB
  * Optionally supports persistence to a file
  */
 export class MemoryStorageAdapter implements IStorageAdapter {
@@ -196,6 +196,18 @@ export class MemoryStorageAdapter implements IStorageAdapter {
     return Array.from(collection.values());
   }
 
+  async findByIds(dbName: string, collName: string, ids: Set<string>): Promise<IStoredDocument[]> {
+    const collection = this.ensureCollection(dbName, collName);
+    const results: IStoredDocument[] = [];
+    for (const id of ids) {
+      const doc = collection.get(id);
+      if (doc) {
+        results.push(doc);
+      }
+    }
+    return results;
+  }
+
   async findById(dbName: string, collName: string, id: plugins.bson.ObjectId): Promise<IStoredDocument | null> {
     const collection = this.ensureCollection(dbName, collName);
     return collection.get(id.toHexString()) || null;

ts/ts_tsmdb/storage/OpLog.ts

@@ -1,4 +1,4 @@
-import * as plugins from '../congodb.plugins.js';
+import * as plugins from '../plugins.js';
 import type { IStorageAdapter } from './IStorageAdapter.js';
 import type { IOpLogEntry, Document, IResumeToken, ChangeStreamOperationType } from '../types/interfaces.js';
 

ts/ts_tsmdb/storage/WAL.ts

@@ -0,0 +1,375 @@
+import * as plugins from '../plugins.js';
+import type { Document, IStoredDocument } from '../types/interfaces.js';
+
+/**
+ * WAL entry operation types
+ */
+export type TWalOperation = 'insert' | 'update' | 'delete' | 'checkpoint' | 'begin' | 'commit' | 'abort';
+
+/**
+ * WAL entry structure
+ */
+export interface IWalEntry {
+  /** Log Sequence Number - monotonically increasing */
+  lsn: number;
+  /** Timestamp of the operation */
+  timestamp: number;
+  /** Operation type */
+  operation: TWalOperation;
+  /** Database name */
+  dbName: string;
+  /** Collection name */
+  collName: string;
+  /** Document ID (hex string) */
+  documentId: string;
+  /** Document data (BSON serialized, base64 encoded) */
+  data?: string;
+  /** Previous document data for updates (for rollback) */
+  previousData?: string;
+  /** Transaction ID if part of a transaction */
+  txnId?: string;
+  /** CRC32 checksum of the entry (excluding this field) */
+  checksum: number;
+}
+
+/**
+ * Checkpoint record
+ */
+interface ICheckpointRecord {
+  lsn: number;
+  timestamp: number;
+  lastCommittedLsn: number;
+}
+
+/**
+ * Write-Ahead Log (WAL) for durability and crash recovery
+ *
+ * The WAL ensures durability by writing operations to a log file before
+ * they are applied to the main storage. On crash recovery, uncommitted
+ * operations can be replayed to restore the database to a consistent state.
+ */
+export class WAL {
+  private walPath: string;
+  private currentLsn: number = 0;
+  private lastCheckpointLsn: number = 0;
+  private entries: IWalEntry[] = [];
+  private isInitialized: boolean = false;
+  private fs = new plugins.smartfs.SmartFs(new plugins.smartfs.SmartFsProviderNode());
+
+  // In-memory uncommitted entries per transaction
+  private uncommittedTxns: Map<string, IWalEntry[]> = new Map();
+
+  // Checkpoint interval (number of entries between checkpoints)
+  private checkpointInterval: number = 1000;
+
+  constructor(walPath: string, options?: { checkpointInterval?: number }) {
+    this.walPath = walPath;
+    if (options?.checkpointInterval) {
+      this.checkpointInterval = options.checkpointInterval;
+    }
+  }
+
+  /**
+   * Initialize the WAL, loading existing entries and recovering if needed
+   */
+  async initialize(): Promise<{ recoveredEntries: IWalEntry[] }> {
+    if (this.isInitialized) {
+      return { recoveredEntries: [] };
+    }
+
+    // Ensure WAL directory exists
+    const walDir = this.walPath.substring(0, this.walPath.lastIndexOf('/'));
+    if (walDir) {
+      await this.fs.directory(walDir).recursive().create();
+    }
+
+    // Try to load existing WAL
+    const exists = await this.fs.file(this.walPath).exists();
+    if (exists) {
+      const content = await this.fs.file(this.walPath).encoding('utf8').read();
+      const lines = (content as string).split('\n').filter(line => line.trim());
+
+      for (const line of lines) {
+        try {
+          const entry = JSON.parse(line) as IWalEntry;
+          // Verify checksum
+          if (this.verifyChecksum(entry)) {
+            this.entries.push(entry);
+            if (entry.lsn > this.currentLsn) {
+              this.currentLsn = entry.lsn;
+            }
+            if (entry.operation === 'checkpoint') {
+              this.lastCheckpointLsn = entry.lsn;
+            }
+          }
+        } catch {
+          // Skip corrupted entries
+          console.warn('Skipping corrupted WAL entry');
+        }
+      }
+    }
+
+    this.isInitialized = true;
+
+    // Return entries after last checkpoint that need recovery
+    const recoveredEntries = this.entries.filter(
+      e => e.lsn > this.lastCheckpointLsn &&
+           (e.operation === 'insert' || e.operation === 'update' || e.operation === 'delete')
+    );
+
+    return { recoveredEntries };
+  }
+
+  /**
+   * Log an insert operation
+   */
+  async logInsert(dbName: string, collName: string, doc: IStoredDocument, txnId?: string): Promise<number> {
+    return this.appendEntry({
+      operation: 'insert',
+      dbName,
+      collName,
+      documentId: doc._id.toHexString(),
+      data: this.serializeDocument(doc),
+      txnId,
+    });
+  }
+
+  /**
+   * Log an update operation
+   */
+  async logUpdate(
+    dbName: string,
+    collName: string,
+    oldDoc: IStoredDocument,
+    newDoc: IStoredDocument,
+    txnId?: string
+  ): Promise<number> {
+    return this.appendEntry({
+      operation: 'update',
+      dbName,
+      collName,
+      documentId: oldDoc._id.toHexString(),
+      data: this.serializeDocument(newDoc),
+      previousData: this.serializeDocument(oldDoc),
+      txnId,
+    });
+  }
+
+  /**
+   * Log a delete operation
+   */
+  async logDelete(dbName: string, collName: string, doc: IStoredDocument, txnId?: string): Promise<number> {
+    return this.appendEntry({
+      operation: 'delete',
+      dbName,
+      collName,
+      documentId: doc._id.toHexString(),
+      previousData: this.serializeDocument(doc),
+      txnId,
+    });
+  }
+
+  /**
+   * Log transaction begin
+   */
+  async logBeginTransaction(txnId: string): Promise<number> {
+    this.uncommittedTxns.set(txnId, []);
+    return this.appendEntry({
+      operation: 'begin',
+      dbName: '',
+      collName: '',
+      documentId: '',
+      txnId,
+    });
+  }
+
+  /**
+   * Log transaction commit
+   */
+  async logCommitTransaction(txnId: string): Promise<number> {
+    this.uncommittedTxns.delete(txnId);
+    return this.appendEntry({
+      operation: 'commit',
+      dbName: '',
+      collName: '',
+      documentId: '',
+      txnId,
+    });
+  }
+
+  /**
+   * Log transaction abort
+   */
+  async logAbortTransaction(txnId: string): Promise<number> {
+    this.uncommittedTxns.delete(txnId);
+    return this.appendEntry({
+      operation: 'abort',
+      dbName: '',
+      collName: '',
+      documentId: '',
+      txnId,
+    });
+  }
+
+  /**
+   * Get entries to roll back for an aborted transaction
+   */
+  getTransactionEntries(txnId: string): IWalEntry[] {
+    return this.entries.filter(e => e.txnId === txnId);
+  }
+
+  /**
+   * Create a checkpoint - marks a consistent point in the log
+   */
+  async checkpoint(): Promise<number> {
+    const lsn = await this.appendEntry({
+      operation: 'checkpoint',
+      dbName: '',
+      collName: '',
+      documentId: '',
+    });
+    this.lastCheckpointLsn = lsn;
+
+    // Truncate old entries (keep only entries after checkpoint)
+    await this.truncate();
+
+    return lsn;
+  }
+
+  /**
+   * Truncate the WAL file, removing entries before the last checkpoint
+   */
+  private async truncate(): Promise<void> {
+    // Keep entries after last checkpoint
+    const newEntries = this.entries.filter(e => e.lsn >= this.lastCheckpointLsn);
+    this.entries = newEntries;
+
+    // Rewrite the WAL file
+    const lines = this.entries.map(e => JSON.stringify(e)).join('\n');
+    await this.fs.file(this.walPath).encoding('utf8').write(lines);
+  }
+
+  /**
+   * Get current LSN
+   */
+  getCurrentLsn(): number {
+    return this.currentLsn;
+  }
+
+  /**
+   * Get entries after a specific LSN (for recovery)
+   */
+  getEntriesAfter(lsn: number): IWalEntry[] {
+    return this.entries.filter(e => e.lsn > lsn);
+  }
+
+  /**
+   * Close the WAL
+   */
+  async close(): Promise<void> {
+    if (this.isInitialized) {
+      // Final checkpoint before close
+      await this.checkpoint();
+    }
+    this.isInitialized = false;
+  }
+
+  // ============================================================================
+  // Private Methods
+  // ============================================================================
+
+  private async appendEntry(
+    partial: Omit<IWalEntry, 'lsn' | 'timestamp' | 'checksum'>
+  ): Promise<number> {
+    await this.initialize();
+
+    this.currentLsn++;
+    const entry: IWalEntry = {
+      ...partial,
+      lsn: this.currentLsn,
+      timestamp: Date.now(),
+      checksum: 0, // Will be calculated
+    };
+
+    // Calculate checksum
+    entry.checksum = this.calculateChecksum(entry);
+
+    // Track in transaction if applicable
+    if (partial.txnId && this.uncommittedTxns.has(partial.txnId)) {
+      this.uncommittedTxns.get(partial.txnId)!.push(entry);
+    }
+
+    // Add to in-memory log
+    this.entries.push(entry);
+
+    // Append to file (append mode for durability)
+    await this.fs.file(this.walPath).encoding('utf8').append(JSON.stringify(entry) + '\n');
+
+    // Check if we need a checkpoint
+    if (this.entries.length - this.lastCheckpointLsn >= this.checkpointInterval) {
+      await this.checkpoint();
+    }
+
+    return entry.lsn;
+  }
+
+  private serializeDocument(doc: Document): string {
+    // Serialize document to BSON and encode as base64
+    const bsonData = plugins.bson.serialize(doc);
+    return Buffer.from(bsonData).toString('base64');
+  }
+
+  private deserializeDocument(data: string): Document {
+    // Decode base64 and deserialize from BSON
+    const buffer = Buffer.from(data, 'base64');
+    return plugins.bson.deserialize(buffer);
+  }
+
+  private calculateChecksum(entry: IWalEntry): number {
+    // Simple CRC32-like checksum
+    const str = JSON.stringify({
+      lsn: entry.lsn,
+      timestamp: entry.timestamp,
+      operation: entry.operation,
+      dbName: entry.dbName,
+      collName: entry.collName,
+      documentId: entry.documentId,
+      data: entry.data,
+      previousData: entry.previousData,
+      txnId: entry.txnId,
+    });
+
+    let crc = 0xFFFFFFFF;
+    for (let i = 0; i < str.length; i++) {
+      crc ^= str.charCodeAt(i);
+      for (let j = 0; j < 8; j++) {
+        crc = (crc >>> 1) ^ (crc & 1 ? 0xEDB88320 : 0);
+      }
+    }
+    return (~crc) >>> 0;
+  }
+
+  private verifyChecksum(entry: IWalEntry): boolean {
+    const savedChecksum = entry.checksum;
+    entry.checksum = 0;
+    const calculatedChecksum = this.calculateChecksum(entry);
+    entry.checksum = savedChecksum;
+    return calculatedChecksum === savedChecksum;
+  }
+
+  /**
+   * Recover document from WAL entry
+   */
+  recoverDocument(entry: IWalEntry): IStoredDocument | null {
+    if (!entry.data) return null;
+    return this.deserializeDocument(entry.data) as IStoredDocument;
+  }
+
+  /**
+   * Recover previous document state from WAL entry (for rollback)
+   */
+  recoverPreviousDocument(entry: IWalEntry): IStoredDocument | null {
+    if (!entry.previousData) return null;
+    return this.deserializeDocument(entry.previousData) as IStoredDocument;
+  }
+}

ts/ts_tsmdb/types/interfaces.ts

@@ -1,4 +1,4 @@
-import type * as plugins from '../congodb.plugins.js';
+import type * as plugins from '../plugins.js';
 
 // ============================================================================
 // Document Types
@@ -14,7 +14,7 @@ export interface WithId<TSchema> {
 // Client Options
 // ============================================================================
 
-export interface ICongoClientOptions {
+export interface ITsmdbClientOptions {
   /** Storage adapter type: 'memory' or 'file' */
   storageType?: 'memory' | 'file';
   /** Path for file-based storage */
@@ -30,7 +30,7 @@ export interface ICongoClientOptions {
 // ============================================================================
 
 export interface IParsedConnectionString {
-  protocol: 'congo';
+  protocol: 'tsmdb';
   storageType: 'memory' | 'file';
   options: {
     persist?: string;

ts/ts_tsmdb/utils/checksum.ts

@@ -0,0 +1,88 @@
+/**
+ * CRC32 checksum utilities for data integrity
+ */
+
+// CRC32 lookup table
+const CRC32_TABLE: number[] = [];
+
+// Initialize the CRC32 table
+function initCRC32Table(): void {
+  if (CRC32_TABLE.length > 0) return;
+
+  for (let i = 0; i < 256; i++) {
+    let crc = i;
+    for (let j = 0; j < 8; j++) {
+      crc = (crc & 1) ? (0xEDB88320 ^ (crc >>> 1)) : (crc >>> 1);
+    }
+    CRC32_TABLE[i] = crc >>> 0;
+  }
+}
+
+/**
+ * Calculate CRC32 checksum for a string
+ */
+export function calculateCRC32(data: string): number {
+  initCRC32Table();
+
+  let crc = 0xFFFFFFFF;
+  for (let i = 0; i < data.length; i++) {
+    const byte = data.charCodeAt(i) & 0xFF;
+    crc = CRC32_TABLE[(crc ^ byte) & 0xFF] ^ (crc >>> 8);
+  }
+  return (~crc) >>> 0;
+}
+
+/**
+ * Calculate CRC32 checksum for a Buffer
+ */
+export function calculateCRC32Buffer(data: Buffer): number {
+  initCRC32Table();
+
+  let crc = 0xFFFFFFFF;
+  for (let i = 0; i < data.length; i++) {
+    crc = CRC32_TABLE[(crc ^ data[i]) & 0xFF] ^ (crc >>> 8);
+  }
+  return (~crc) >>> 0;
+}
+
+/**
+ * Calculate checksum for a document (serialized as JSON)
+ */
+export function calculateDocumentChecksum(doc: Record<string, any>): number {
+  // Exclude _checksum field from calculation
+  const { _checksum, ...docWithoutChecksum } = doc;
+  const json = JSON.stringify(docWithoutChecksum);
+  return calculateCRC32(json);
+}
+
+/**
+ * Add checksum to a document
+ */
+export function addChecksum<T extends Record<string, any>>(doc: T): T & { _checksum: number } {
+  const checksum = calculateDocumentChecksum(doc);
+  return { ...doc, _checksum: checksum };
+}
+
+/**
+ * Verify checksum of a document
+ * Returns true if checksum is valid or if document has no checksum
+ */
+export function verifyChecksum(doc: Record<string, any>): boolean {
+  if (!('_checksum' in doc)) {
+    // No checksum to verify
+    return true;
+  }
+
+  const storedChecksum = doc._checksum;
+  const calculatedChecksum = calculateDocumentChecksum(doc);
+
+  return storedChecksum === calculatedChecksum;
+}
+
+/**
+ * Remove checksum from a document
+ */
+export function removeChecksum<T extends Record<string, any>>(doc: T): Omit<T, '_checksum'> {
+  const { _checksum, ...docWithoutChecksum } = doc;
+  return docWithoutChecksum as Omit<T, '_checksum'>;
+}

ts/ts_tsmdb/utils/index.ts

@@ -0,0 +1 @@
+export * from './checksum.js';