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https://github.com/canonical/dqlite?tab=readme-ov-file

Embeddable, replicated and fault-tolerant SQL engine.
https://github.com/canonical/dqlite?tab=readme-ov-file

database raft sqlite

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Embeddable, replicated and fault-tolerant SQL engine.

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README 

        
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======



[English](./README.md)|[简体中文](./README_CH.md)



[dqlite](https://dqlite.io) is a C library that implements an embeddable and

replicated SQL database engine with high availability and automatic failover.



The acronym "dqlite" stands for "distributed SQLite", meaning that dqlite

extends [SQLite](https://sqlite.org/) with a network protocol that can connect

together various instances of your application and have them act as a

highly-available cluster, with no dependency on external databases.



Design highlights

----------------



* Asynchronous single-threaded implementation using [libuv](https://libuv.org/)

  as event loop.

* Custom wire protocol optimized for SQLite primitives and data types.

* Data replication based on the [Raft](https://raft.github.io/) algorithm.



License

-------



The dqlite library is released under a slightly modified version of LGPLv3,

that includes a copyright exception allowing users to statically link the

library code in their project and release the final work under their own terms.

See the full [license](https://github.com/canonical/dqlite/blob/master/LICENSE)

text.



Compatibility

-------------



dqlite runs on Linux and requires a kernel with support for [native async

I/O](https://man7.org/linux/man-pages/man2/io_setup.2.html) (not to be confused

with [POSIX AIO](https://man7.org/linux/man-pages/man7/aio.7.html)).



Try it

-------



The simplest way to see dqlite in action is to use the demo program that comes

with the Go dqlite bindings. Please see the [relevant

documentation](https://github.com/canonical/go-dqlite#demo) in that project.



Media

-----



A talk about dqlite was given at FOSDEM 2020, you can watch it

[here](https://fosdem.org/2020/schedule/event/dqlite/).



[Here](https://gcore.com/blog/comparing-litestream-rqlite-dqlite/) is a blog

post from 2022 comparing dqlite with rqlite and Litestream, other replication

software for SQLite.



Wire protocol

-------------



If you wish to write a client, please refer to the [wire

protocol](https://dqlite.io/docs/protocol) documentation.



Install

-------



If you are on a Debian-based system, you can get the latest development release

from dqlite's [dev PPA](https://launchpad.net/~dqlite/+archive/ubuntu/dev):



```

sudo add-apt-repository ppa:dqlite/dev

sudo apt update

sudo apt install libdqlite-dev

```



Contributing

------------



See [CONTRIBUTING.md](./CONTRIBUTING.md).



Build

-----



To build libdqlite from source you'll need:



* Build dependencies: pkg-config and GNU Autoconf, Automake, libtool, and make

* A reasonably recent version of [libuv](https://libuv.org/) (v1.8.0 or later), with headers.

* A reasonably recent version of [SQLite](https://sqlite.org/) (v3.22.0 or later), with headers.

* Optionally, a reasonably recent version of [LZ4](https://lz4.org/) (v1.7.1 or later), with headers.



Your distribution should already provide you with these dependencies. For

example, on Debian-based distros:



```

sudo apt install pkg-config autoconf automake libtool make libuv1-dev libsqlite3-dev liblz4-dev

```



With these dependencies installed, you can build and install the dqlite shared

library and headers as follows:



```

$ autoreconf -i

$ ./configure --enable-build-raft

$ make

$ sudo make install

```



The default installation prefix is `/usr/local`; you may need to run



```

$ sudo ldconfig

```



to enable the linker to find `libdqlite.so`. To install to a different prefix,

replace the configure step with something like



```

$ ./configure --enable-build-raft --prefix=/usr

```



The `--enable-build-raft` option causes dqlite to use its bundled Raft

implementation instead of linking to an external libraft; the latter is a

legacy configuration that should not be used for new development.



Building for static linking

---------------------------



If you're building dqlite for eventual use in a statically-linked

binary, there are some additional considerations. You should pass

`--with-static-deps` to the configure script; this disables code that

relies on dependencies being dynamically linked. (Currently it only

affects the test suite, but you should use it even when building

`libdqlite.a` only for future compatibility.)



When linking libdqlite with musl libc, it's recommended to increase

the default stack size, which is otherwise too low for dqlite's

needs:



```

LDFLAGS="-Wl,-z,stack-size=1048576"

```



The `contrib/build-static.sh` script demonstrates building and

testing dqlite with all dependencies (including libc) statically

linked.



Usage Notes

-----------



Detailed tracing will be enabled when the environment variable

`LIBDQLITE_TRACE` is set before startup.  The value of it can be in `[0..5]`

range and reperesents a tracing level, where `0` means "no traces" emitted, `5`

enables minimum (FATAL records only), and `1` enables maximum verbosity (all:

DEBUG, INFO, WARN, ERROR, FATAL records).