Closes #1384 . This PR implements Primary Key constraint for inserts. As can be seen in the issue, if you created an Index with a Primary Key constraint, it could trigger `Unique Constraint` error, but still insert the record. Sqlite uses the opcode `NoConflict` to check if the record already exists in the Btree. As we did not have this Opcode yet, I implemented it. It is very similar to `NotFound` with the difference that if any value in the Record is Null, it will immediately jump to the offset. The added benefit of implementing this, is that now we fully support Composite Primary Keys. Also, I think with the current implementation, it will be trivial to implement the Unique opcode for Insert. To support Updates, I need to understand more of the plan optimizer to and find where we are Making the Record and opening the autoindex. For testing, I have written a test generator to generate many different tables that can have a varying numbers of Primary Keys. ```sql limbo> CREATE TABLE users (id INT, username TEXT, PRIMARY KEY (id, username)); limbo> INSERT INTO users VALUES (1, 'alice'); limbo> explain INSERT INTO users VALUES (1, 'alice'); addr opcode p1 p2 p3 p4 p5 comment ---- ----------------- ---- ---- ---- ------------- -- ------- 0 Init 0 16 0 0 Start at 16 1 OpenWrite 0 2 0 0 2 Integer 1 2 0 0 r[2]=1 3 String8 0 3 0 alice 0 r[3]='alice' 4 OpenWrite 1 3 0 0 5 NewRowId 0 1 0 0 6 Copy 2 5 0 0 r[5]=r[2] 7 Copy 3 6 0 0 r[6]=r[3] 8 Copy 1 7 0 0 r[7]=r[1] 9 MakeRecord 5 3 8 0 r[8]=mkrec(r[5..7]) 10 NoConflict 1 12 5 2 0 key=r[5] 11 Halt 1555 0 0 users.id, users.username 0 12 IdxInsert 1 8 5 0 key=r[8] 13 MakeRecord 2 2 4 0 r[4]=mkrec(r[2..3]) 14 Insert 0 4 1 0 15 Halt 0 0 0 0 16 Transaction 0 1 0 0 write=true 17 Goto 0 1 0 0 limbo> INSERT INTO users VALUES (1, 'alice'); × Runtime error: UNIQUE constraint failed: users.id, users.username (19) limbo> INSERT INTO users VALUES (1, 'bob'); limbo> INSERT INTO users VALUES (1, 'bob'); × Runtime error: UNIQUE constraint failed: users.id, users.username (19) ``` Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com> Closes #1393
Project Limbo
Limbo is a project to build the modern evolution of SQLite.
Features and Roadmap
Limbo is a work-in-progress, in-process OLTP database engine library written in Rust that has:
- Asynchronous I/O support on Linux with
io_uring - SQLite compatibility [doc] for SQL dialect, file formats, and the C API
- Language bindings for JavaScript/WebAssembly, Rust, Go, Python, and Java
- OS support for Linux, macOS, and Windows
In the future, we will be also working on:
- Integrated vector search for embeddings and vector similarity.
BEGIN CONCURRENTfor improved write throughput.- Improved schema management including better
ALTERsupport and strict column types by default.
Getting Started
💻 Command Line
You can install the latest `limbo` release with:
curl --proto '=https' --tlsv1.2 -LsSf \
https://github.com/tursodatabase/limbo/releases/latest/download/limbo_cli-installer.sh | sh
Then launch the shell to execute SQL statements:
Limbo
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database
limbo> CREATE TABLE users (id INT PRIMARY KEY, username TEXT);
limbo> INSERT INTO users VALUES (1, 'alice');
limbo> INSERT INTO users VALUES (2, 'bob');
limbo> SELECT * FROM users;
1|alice
2|bob
You can also build and run the latest development version with:
cargo run
🦀 Rust
cargo add limbo
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 limbo-wasm
Example usage:
import { Database } from 'limbo-wasm';
const db = new Database('sqlite.db');
const stmt = db.prepare('SELECT * FROM users');
const users = stmt.all();
console.log(users);
🐍 Python
pip install pylimbo
Example usage:
import limbo
con = limbo.connect("sqlite.db")
cur = con.cursor()
res = cur.execute("SELECT * FROM users")
print(res.fetchone())
🐹 Go
- Clone the repository
- Build the library and set your LD_LIBRARY_PATH to include limbo's target directory
cargo build --package limbo-go
export LD_LIBRARY_PATH=/path/to/limbo/target/debug:$LD_LIBRARY_PATH
- Use the driver
go get github.com/tursodatabase/limbo
go install github.com/tursodatabase/limbo
Example usage:
import (
"database/sql"
_"github.com/tursodatabase/limbo"
)
conn, _ = sql.Open("sqlite3", "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 Limbo into JDBC. For detailed instructions on how to use Limbo with java, please refer to the README.md under bindings/java.
Contributing
We'd love to have you contribute to Limbo! Please check out the contribution guide to get started.
FAQ
How is Limbo different from Turso's libSQL?
Limbo is a project to build the modern 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, Limbo is not - although it is evolving rapidly. As the project starts to near production readiness, we plan to rename it to just "Turso". 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 Limbo by you, shall be licensed as MIT, without any additional terms or conditions.
Contributors
Thanks to all the contributors to Limbo!
