README

This is an implementation of the LevelDB key/value database in the Go programming language.

Build Status

Installation

go get github.com/pingcap/goleveldb/leveldb

Requirements

  • Need at least go1.4 or newer.

Usage

Create or open a database:

// The returned DB instance is safe for concurrent use. Which mean that all
// DB's methods may be called concurrently from multiple goroutine.
db, err := leveldb.OpenFile("path/to/db", nil)
...
defer db.Close()
...

Read or modify the database content:

// Remember that the contents of the returned slice should not be modified.
data, err := db.Get([]byte("key"), nil)
...
err = db.Put([]byte("key"), []byte("value"), nil)
...
err = db.Delete([]byte("key"), nil)
...

Iterate over database content:

iter := db.NewIterator(nil, nil)
for iter.Next() {
	// Remember that the contents of the returned slice should not be modified, and
	// only valid until the next call to Next.
	key := iter.Key()
	value := iter.Value()
	...
}
iter.Release()
err = iter.Error()
...

Seek-then-Iterate:

iter := db.NewIterator(nil, nil)
for ok := iter.Seek(key); ok; ok = iter.Next() {
	// Use key/value.
	...
}
iter.Release()
err = iter.Error()
...

Iterate over subset of database content:

iter := db.NewIterator(&util.Range{Start: []byte("foo"), Limit: []byte("xoo")}, nil)
for iter.Next() {
	// Use key/value.
	...
}
iter.Release()
err = iter.Error()
...

Iterate over subset of database content with a particular prefix:

iter := db.NewIterator(util.BytesPrefix([]byte("foo-")), nil)
for iter.Next() {
	// Use key/value.
	...
}
iter.Release()
err = iter.Error()
...

Batch writes:

batch := new(leveldb.Batch)
batch.Put([]byte("foo"), []byte("value"))
batch.Put([]byte("bar"), []byte("another value"))
batch.Delete([]byte("baz"))
err = db.Write(batch, nil)
...

Use bloom filter:

o := &opt.Options{
	Filter: filter.NewBloomFilter(10),
}
db, err := leveldb.OpenFile("path/to/db", o)
...
defer db.Close()
...

Documentation

You can read package documentation here.

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Directories

Path Synopsis
Package leveldb provides implementation of LevelDB key/value database.
Package leveldb provides implementation of LevelDB key/value database.
cache
Package cache provides interface and implementation of a cache algorithms.
Package cache provides interface and implementation of a cache algorithms.
comparer
Package comparer provides interface and implementation for ordering sets of data.
Package comparer provides interface and implementation for ordering sets of data.
errors
Package errors provides common error types used throughout leveldb.
Package errors provides common error types used throughout leveldb.
filter
Package filter provides interface and implementation of probabilistic data structure.
Package filter provides interface and implementation of probabilistic data structure.
iterator
Package iterator provides interface and implementation to traverse over contents of a database.
Package iterator provides interface and implementation to traverse over contents of a database.
journal
Package journal reads and writes sequences of journals.
Package journal reads and writes sequences of journals.
memdb
Package memdb provides in-memory key/value database implementation.
Package memdb provides in-memory key/value database implementation.
opt
Package opt provides sets of options used by LevelDB.
Package opt provides sets of options used by LevelDB.
storage
Package storage provides storage abstraction for LevelDB.
Package storage provides storage abstraction for LevelDB.
table
Package table allows read and write sorted key/value.
Package table allows read and write sorted key/value.
util
Package util provides utilities used throughout leveldb.
Package util provides utilities used throughout leveldb.
manualtest