README

LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.

 This repository is receiving very limited maintenance. We will only review the following types of changes.

  Fixes for critical bugs, such as data loss or memory corruption
  Changes absolutely needed by internally supported leveldb clients. These typically fix breakage introduced by a language/standard library/OS update



Authors: Sanjay Ghemawat ([email protected]) and Jeff Dean ([email protected])

 Features

   Keys and values are arbitrary byte arrays.
   Data is stored sorted by key.
   Callers can provide a custom comparison function to override the sort order.
   The basic operations are Put(key,value), Get(key), Delete(key).
   Multiple changes can be made in one atomic batch.
   Users can create a transient snapshot to get a consistent view of data.
   Forward and backward iteration is supported over the data.
   Data is automatically compressed using the Snappy compression library, but Zstd compression is also supported.
   External activity (file system operations etc.) is relayed through a virtual interface so users can customize the operating system interactions.

 Documentation

  LevelDB library documentation is online and bundled with the source code.

 Limitations

   This is not a SQL database.  It does not have a relational data model, it does not support SQL queries, and it has no support for indexes.
   Only a single process (possibly multi-threaded) can access a particular database at a time.
   There is no client-server support builtin to the library.  An application that needs such support will have to wrap their own server around the library.

 Getting the Source

bash
git clone --recurse-submodules https://github.com/google/leveldb.git


 Building

This project supports CMake out of the box.

 Build for POSIX

Quick start:

bash
mkdir -p build && cd build
cmake -DCMAKE_BUILD_TYPE=Release .. && cmake --build .


 Building for Windows

First generate the Visual Studio 2017 project/solution files:

cmd
mkdir build
cd build
cmake -G "Visual Studio 15" ..

The default default will build for x86. For 64-bit run:

cmd
cmake -G "Visual Studio 15 Win64" ..


To compile the Windows solution from the command-line:

cmd
devenv /build Debug leveldb.sln


or open leveldb.sln in Visual Studio and build from within.

Please see the CMake documentation and CMakeLists.txt for more advanced usage.

 Contributing to the leveldb Project

 This repository is receiving very limited maintenance. We will only review the following types of changes.

  Bug fixes
  Changes absolutely needed by internally supported leveldb clients. These typically fix breakage introduced by a language/standard library/OS update

The leveldb project welcomes contributions. leveldb's primary goal is to be
a reliable and fast key/value store. Changes that are in line with the
features/limitations outlined above, and meet the requirements 

Top issues

Latest release

Sync MANIFEST before closing in db_impl when creating a new DB. Add logging with debugging information when failing to load a version set.
 Optimize leveldb block seeks to utilize the current iterator location. This is beneficial when iterators are reused and seeks are not random but increasing. It is additionally beneficial with larger block sizes and keys with common prefixes.
 Merge pull request 862 from rex4539:https
 Documentation fixes
 Merge pull request 855 from cmumford/submodule-fix
 (test) Merge pull request 853 from cmumford:benchmark
 Merge pull request 854 from cmumford:pri