Leo-Lionni / PoloDB

PoloDB is an embedded JSON-based database.

PoloDB

PoloDB is an embedded JSON-based database.

中文版

Features

• Simple and Lightweight
  • Only cost ~500kb memory to serve a database
  • The database server binary is less than 2Mb
• Easy to learn and use
  • NoSQL
  • MongoDB-like API
• Various language bindings
• Can be embedded or standalone
  • Embedded Mode
    • No standalone processes
    • No cross-process calls
    • No runtime dependency
  • Standalone: Run as a process, communicate with IPC
• Cross-Platform
• Multiple backends
  • Filesystem(WAL)
  • Memory

Filesystem Backend

With the filesystem backend, PoloDB stores data in ONE file. All the data are saved persistently on the disk.

It's designed to be flexible, universal, and easy to be searched. All the data are encoded in msgpack format and stored in the PoloDB's btree format.

PoloDB uses WAL(write-ahead logging) to implement transactional writing and protect your data from program crashes.

Memory Backend

With the memory backend, all the data all stored in memory, making PoloDB a pure memory database.

Introduction

PoloDB is a library written in Rust that implements a lightweight MongoDB.

PoloDB has no dependency(except for libc), so it can be easily run on most platforms (thanks for Rust Language).

The data of PoloDB is stored in a file. The file format is stable, cross-platform, and backwards compatible.

The API of PoloDB is very similar to MongoDB. It's very easy to learn and use.

Platform

Theoretically, PoloDB supports all platforms that the Rust compiler supports. But PoloDB is a personal project currently. Limited by my time, I have only compiled and tested on the following platforms:

• macOS Big Sur x64
• Linux x64 (Tested on Fedora 32)
• Windows 10 x64

Manual

• Rust
• Node.js
• Python

Developing Plan

The features will be implemented one by one in order.

• Basic database API
  • CRUD
  • Transactions
  • Indexes
  • Aggregation
• Command line Tools
• Language bindings
  • C/C++
  • Python (Doc)
  • Node.js
• Multi-threads support
• Extension API
  • Data Encryption
  • JavaScript Engine
• Visualization Tools

V1 to V2

PoloDB V2 uses msgpack to encode data.

PoloDB V1 uses custom format.

Migration

Rust

Database::v1_to_v2 can be used to migrate from v1 to v2.

Tool

polodb migrate --target v2 ./mydb

Contribute

Module	Path	Description
Core	src/polodb_core	The core implementation of the Database
C Library	src/polodb_clib	The C FFI implementation of PoloDB
CLI tool	src/polodb	The command line tool of PoloDB
Node.js	polodb.js	The Node.js binding using N-API
Python bindings	pypolodb	The CPython binding using Extension API