CalicoDB is a tiny key-value database library written in C++17 and inspired by SQLite3. It exposes a small API that allows transactional storage and retrieval of byte sequences from multiple key spaces. CalicoDB aims to be portable, flexible, and simple.
CalicoDB is under active development. It is not ready for production, and the author is not a professional database developer. Feedback is appreciated!
- Records are stored in buckets, each with an independent sorted range of keys
- All buckets are stored in the same file, similar to the SQLite database file format
- Supports multiple readers and a single writer simultaneously (readers have snapshot isolation)
- Per-bucket bidirectional iteration using cursors
- Live defragmentation is supported
- Allows nested buckets
- In-memory databases
- Virtual WAL interface
- Keys, values, and bucket names are limited to roughly 2 GB in length
- Each connection is single-threaded, and blocking I/O is used
- Concurrent usage requires each connection to have its own
DB - Only practical for datasets that can reasonably be stored in a single file
- Platform must support shared-memory primitives (otherwise, may work in "exclusive locking mode")
Check out the docs.
The library requires the following to compile:
- CMake version 3.14 or later
- C++ compiler with support for C++17
- GCC (>= 7.0)
- Clang (>= 5.0)
The tests depend on:
@google/googletest(downloaded with CMake FetchContent)- Python 3
Performance benchmarks are run in a fork of LevelDB. Recent results can be found here.
- Get everything code reviewed!
- Support Windows (write an
Envimplementation)
Check out CalicoDB's usage and design documents. Build instructions can be found here.
Contributions are welcome! Check out this repo's issues or the TODO section for a list of things that need to be addressed.