Pekka Enberg 810ed8ad60 Merge 'Don't allow autovacuum to be flipped on non-empty databases' from Pavan Nambi
Turso incorrectly creates the first table in an autovacuumed table in
page 2.
(Note: this is on collaboration with @LeMikaelF)
SQLite does not allow enabling or disabling auto-vacuum after the first
table has been created
(https://sqlite.org/pragma.html#pragma_auto_vacuum). This is because the
sequence of the pages in the databases is different when auto-vacuum is
enabled, because the first b-tree page must be page 3 instead of 2, to
make room for the first [Pointer Map
page](https://sqlite.org/fileformat.html#pointer_map_or_ptrmap_pages).
But Turso doesn't currently consider this, which can lead to data loss.
The simplest way to reproduce this is to create an autovacuumed
databases with either `pragma auto_vacuum=full` so that autovacuum runs
on each commit, and then create a table with some data. Turso will
incorrectly create the new table on page 2. After this, every time a new
page is created, either through a page split or because a new table is
created, Turso will write a 5-byte pointer in page 2, starting from the
top of the page, thereby overwriting existing data.
For example, let's start with a clean database and the first bytes of
page 2. It starts with `0d`, the discriminator for a leaf page
([source](https://www.sqlite.org/fileformat.html#b_tree_pages)). The
next interesting number is the number of cells contained in this page
(`01`) at offset 5.
```
$ cargo run -- /tmp/a.db
turso> create table t(a);
turso> insert into t values ('myvalue');

$ dbtotxt /tmp/a.db
| size 8192 pagesize 4096 filename a.db
| page 1 offset 0
# ...snip...
| page 2 offset 4096
|      0: 0d 00 00 00 01 0f f5 00 0f f5 00 00 00 00 00 00   ................
|   4080: 00 00 00 00 00 09 01 02 1b 6d 79 76 61 6c 75 65   .........myvalue
| end a.db
```
Pointer map pages are located every N pages, starting from page 2, and
contain a list of 5-byte pointers that represent the parent page of a
certain page. So whenever Turso or SQLite needs to add a page, it will
overwrite 5 bytes of page 2. This means that for data loss to occur, it
is sufficient to add a single page to the database, for example by
creating a table. Offset 5 will then be zeroed out:
```
$ cargo run -- /tmp/a.db
turso> create table t(a);
turso> insert into t values ('myvalue');
turso> pragma auto_vacuum=full;
turso> create table tt(a);

$ dbtotxt /tmp/a.db
| size 12288 pagesize 4096 filename a.db
| page 1 offset 0
# ...snip...
| page 2 offset 4096
|      0: 01 00 00 00 00 0f f5 00 0f f5 00 00 00 00 00 00   ................
|   4080: 00 00 00 00 00 09 01 02 1b 6d 79 76 61 6c 75 65   .........myvalue
```
Creating more tables, or adding more B-tree pages, will keep overwriting
the rest of the page, until the cells themselves are also overwritten.
## Reproducing the issue in the simulator
We have been unable to reproduce this exact corruption mode in the
simulator, but patching it shows many failure modes, all of which don't
occur with the unpatched simulator. The following seeds are failing. The
following seeds are showing the issue when the patched simulator is ran
against `main`:
- `11522841279124073062`, with "Assertion 'table inquisitive_graham_159
should contain all of its expected values' failed: table
inquisitive_graham_159 does not contain the expected values, the
simulator model has more rows than the database"
- `7057400018220918989`, `16028085350691325843`, `7721542713659053944`,
and `203017821863546118`, with "Failed to read ptrmap key=XXX"
- `12533694709304969540`, `18357088553315413457`, `3108945730906932377`,
with "Integrity Check Failed: Cell N in page 2 is out of range."
    - `4757352625344646473`, with "dirty pages should be empty for read
txn"
- `7083498604824302257`, with "header_size: 6272, header_len_bytes: 2,
payload.len(): 13"
- `17881876827470741581`, with "ParseError("no such table:
focused_historians_416")"
- `2092231500503735693`, with "range end index 4789 out of range for
slice of length 4096"
- `7555257419378470845`, with malformed database schema
(imaginative_ontivero\u{1})"
- `12905270229511147245`, with "index out of bounds: the len is 4096 but
the index is 4096"
## Fixing the issue
- When DB is opened, we read the `auto_vacuum` state, instead of
assuming `auto_vacuum=none`.
- Don't allow auto_vacuum to be flipped on non-empty databases as if we
allow this it could cause overlap with existing bits.(ptrmap could
overwrite existing data)
- Modify integrity check to avoid reporting that page 2 is orphaned in
auto-vacuumed databases.
Fixes #3752

Closes #3830
2025-10-28 14:48:35 +02:00
2025-08-08 15:45:05 +04:00
2025-10-27 07:09:02 +02:00
2025-09-27 14:13:45 -04:00
2025-10-06 18:19:22 +04:00
2025-09-26 15:20:27 +07:00
2025-09-24 18:06:55 -03:00
2025-03-29 14:46:11 +02:00
2025-10-24 19:35:13 +05:30
2025-10-24 19:35:13 +05:30
2025-10-20 23:48:19 -05:00
2025-10-06 11:07:06 -03:00
2025-10-27 16:10:49 +02:00
2025-01-14 18:37:26 +02:00
2025-04-15 12:45:46 -03:00
2025-10-22 13:42:52 +03:00
2025-10-03 12:20:20 +03:00
2025-07-30 11:45:24 +02:00
2025-07-17 20:25:40 -03:00
2024-07-12 13:07:34 -07:00
2024-07-12 12:38:56 -07:00
2025-10-08 09:20:44 +03:00

Turso Database

Turso Database

An in-process SQL database, compatible with SQLite.

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Chat with other users of Turso (and Turso Cloud) on Discord


About

Turso Database is an in-process SQL database written in Rust, compatible with SQLite.

⚠️ Warning: This software is in BETA. It may still contain bugs and unexpected behavior. Use caution with production data and ensure you have backups.

Features and Roadmap

  • SQLite compatibility for SQL dialect, file formats, and the C API [see document for details]
  • Change data capture (CDC) for real-time tracking of database changes.
  • Multi-language support for
  • Asynchronous I/O support on Linux with io_uring
  • Cross-platform support for Linux, macOS, Windows and browsers (through WebAssembly)
  • Vector support support including exact search and vector manipulation
  • Improved schema management including extended ALTER support and faster schema changes.

The database has the following experimental features:

  • BEGIN CONCURRENT for improved write throughput using multi-version concurrency control (MVCC).
  • Encryption at rest for protecting the data locally.
  • Incremental computation using DBSP for incremental view mainatenance and query subscriptions.

The following features are on our current roadmap:

Getting Started

Please see the Turso Database Manual for more information.

💻 Command Line
You can install the latest `turso` release with:
curl --proto '=https' --tlsv1.2 -LsSf \
  https://github.com/tursodatabase/turso/releases/latest/download/turso_cli-installer.sh | sh

Then launch the interactive shell:

$ tursodb

This will start the Turso interactive shell where you can execute SQL statements:

Turso
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database
turso> CREATE TABLE users (id INT, username TEXT);
turso> INSERT INTO users VALUES (1, 'alice');
turso> INSERT INTO users VALUES (2, 'bob');
turso> SELECT * FROM users;
1|alice
2|bob

You can also build and run the latest development version with:

cargo run

If you like docker, we got you covered. Simply run this in the root folder:

make docker-cli-build && \
make docker-cli-run
🦀 Rust
cargo add turso

Example usage:

let db = Builder::new_local("sqlite.db").build().await?;
let conn = db.connect()?;

let res = conn.query("SELECT * FROM users", ()).await?;
JavaScript
npm i @tursodatabase/database

Example usage:

import { connect } from '@tursodatabase/database';

const db = await connect('sqlite.db');
const stmt = db.prepare('SELECT * FROM users');
const users = stmt.all();
console.log(users);
🐍 Python
uv pip install pyturso

Example usage:

import turso

con = turso.connect("sqlite.db")
cur = con.cursor()
res = cur.execute("SELECT * FROM users")
print(res.fetchone())
🦫 Go
go get github.com/tursodatabase/turso-go
go install github.com/tursodatabase/turso-go

Example usage:

import (
    "database/sql"
    _ "github.com/tursodatabase/turso-go"
)

conn, _ = sql.Open("turso", "sqlite.db")
defer conn.Close()

stmt, _ := conn.Prepare("select * from users")
defer stmt.Close()

rows, _ = stmt.Query()
for rows.Next() {
    var id int
    var username string
    _ := rows.Scan(&id, &username)
    fmt.Printf("User: ID: %d, Username: %s\n", id, username)
}
Java

We integrated Turso Database into JDBC. For detailed instructions on how to use Turso Database with java, please refer to the README.md under bindings/java.

🤖 MCP Server Mode

The Turso CLI includes a built-in Model Context Protocol (MCP) server that allows AI assistants to interact with your databases.

Start the MCP server with:

tursodb your_database.db --mcp

Configuration

Add Turso to your MCP client configuration:

{
  "mcpServers": {
    "turso": {
      "command": "/path/to/.turso/tursodb",
      "args": ["/path/to/your/database.db", "--mcp"]
    }
  }
}

Available Tools

The MCP server provides nine tools for database interaction:

  1. open_database - Open a new database
  2. current_database - Describe the current database
  3. list_tables - List all tables in the database
  4. describe_table - Describe the structure of a specific table
  5. execute_query - Execute read-only SELECT queries
  6. insert_data - Insert new data into tables
  7. update_data - Update existing data in tables
  8. delete_data - Delete data from tables
  9. schema_change - Execute schema modification statements (CREATE TABLE, ALTER TABLE, DROP TABLE)

Once connected, you can ask your AI assistant:

  • "Show me all tables in the database"
  • "What's the schema for the users table?"
  • "Find all posts with more than 100 upvotes"
  • "Insert a new user with name 'Alice' and email 'alice@example.com'"

MCP Clients

Claude Code

If you're using Claude Code, you can easily connect to your Turso MCP server using the built-in MCP management commands:

Quick Setup

  1. Add the MCP server to Claude Code:

    claude mcp add my-database -- tursodb ./path/to/your/database.db --mcp
    
  2. Restart Claude Code to activate the connection

  3. Start querying your database through natural language!

Command Breakdown

claude mcp add my-database -- tursodb ./path/to/your/database.db --mcp
#              ↑            ↑       ↑                           ↑
#              |            |       |                           |
#              Name         |       Database path               MCP flag
#                          Separator
  • my-database - Choose any name for your MCP server
  • -- - Required separator between Claude options and your command
  • tursodb - The Turso database CLI
  • ./path/to/your/database.db - Path to your SQLite database file
  • --mcp - Enables MCP server mode

Example Usage

# For a local project database
cd /your/project
claude mcp add my-project-db -- tursodb ./data/app.db --mcp

# For an absolute path
claude mcp add analytics-db -- tursodb /Users/you/databases/analytics.db --mcp

# For a specific project (local scope)
claude mcp add project-db --local -- tursodb ./database.db --mcp

Managing MCP Servers

# List all configured MCP servers
claude mcp list

# Get details about a specific server
claude mcp get my-database

# Remove an MCP server
claude mcp remove my-database
Claude Desktop

For Claude Desktop, add the configuration to your claude_desktop_config.json file:

{
  "mcpServers": {
    "turso": {
      "command": "/path/to/.turso/tursodb",
      "args": ["./path/to/your/database.db.db", "--mcp"]
    }
  }
}
Cursor

For Cursor, configure MCP in your settings:

  1. Open Cursor settings
  2. Navigate to Extensions → MCP
  3. Add a new server with:
    • Name: turso
    • Command: /path/to/.turso/tursodb
    • Args: ["./path/to/your/database.db.db", "--mcp"]

Alternatively, you can add it to your Cursor configuration file directly.

Direct JSON-RPC Usage

The MCP server runs as a single process that handles multiple JSON-RPC requests over stdin/stdout. Here's how to interact with it directly:

Example with In-Memory Database

cat << 'EOF' | tursodb --mcp
{"jsonrpc": "2.0", "id": 1, "method": "initialize", "params": {"protocolVersion": "2024-11-05", "capabilities": {}, "clientInfo": {"name": "client", "version": "1.0"}}}
{"jsonrpc": "2.0", "id": 2, "method": "tools/call", "params": {"name": "schema_change", "arguments": {"query": "CREATE TABLE users (id INTEGER, name TEXT, email TEXT)"}}}
{"jsonrpc": "2.0", "id": 3, "method": "tools/call", "params": {"name": "list_tables", "arguments": {}}}
{"jsonrpc": "2.0", "id": 4, "method": "tools/call", "params": {"name": "insert_data", "arguments": {"query": "INSERT INTO users VALUES (1, 'Alice', 'alice@example.com')"}}}
{"jsonrpc": "2.0", "id": 5, "method": "tools/call", "params": {"name": "execute_query", "arguments": {"query": "SELECT * FROM users"}}}
EOF

Example with Existing Database

# Working with an existing database file
cat << 'EOF' | tursodb mydb.db --mcp
{"jsonrpc": "2.0", "id": 1, "method": "initialize", "params": {"protocolVersion": "2024-11-05", "capabilities": {}, "clientInfo": {"name": "client", "version": "1.0"}}}
{"jsonrpc": "2.0", "id": 2, "method": "tools/call", "params": {"name": "list_tables", "arguments": {}}}
EOF

Contributing

We'd love to have you contribute to Turso Database! Please check out the contribution guide to get started.

Found a data corruption bug? Get up to $1,000.00

SQLite is loved because it is the most reliable database in the world. The next evolution of SQLite has to match or surpass this level of reliability. Turso is built with Deterministic Simulation Testing from the ground up, and is also tested by Antithesis.

Even during Alpha, if you find a bug that leads to a data corruption and demonstrate how our simulator failed to catch it, you can get up to $1,000.00. As the project matures we will increase the size of the prize, and the scope of the bugs.

More details here.

You can see an example of an awarded case on #2049.

Turso core staff are not eligible.

FAQ

Is Turso Database ready for production use?

Turso Database is currently under heavy development and is not ready for production use.

How is Turso Database different from Turso's libSQL?

Turso Database is a project to build the next evolution of SQLite in Rust, with a strong open contribution focus and features like native async support, vector search, and more. The libSQL project is also an attempt to evolve SQLite in a similar direction, but through a fork rather than a rewrite.

Rewriting SQLite in Rust started as an unassuming experiment, and due to its incredible success, replaces libSQL as our intended direction. At this point, libSQL is production ready, Turso Database is not - although it is evolving rapidly. More details here.

Publications

  • Pekka Enberg, Sasu Tarkoma, Jon Crowcroft Ashwin Rao (2024). Serverless Runtime / Database Co-Design With Asynchronous I/O. In EdgeSys 24. [PDF]
  • Pekka Enberg, Sasu Tarkoma, and Ashwin Rao (2023). Towards Database and Serverless Runtime Co-Design. In CoNEXT-SW 23. [PDF] [Slides]

License

This project is licensed under the MIT license.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Turso Database by you, shall be licensed as MIT, without any additional terms or conditions.

Partners

Thanks to all the partners of Turso!

Contributors

Thanks to all the contributors to Turso Database!

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