leveldb: partially rewrite batch and db writer

The new batch implementation is more cleaner by spliting batch header
buffer. Also added index, replaying batch should be much more performant now.

DB writer now guarantee that user batch content won't be changed, previous
implementation would append batch directly into user batch during write
merge, this plain wrong and can potentially cause issue. Also added options
to disable write merge.

There are internal corruption detected on issue #155, the batch apparently
contains invalid batch header and record with invalid length. Also lots
of batches with invalid sequence number present in the journal. Hopefully
this change fixes some of that.
10 files changed
tree: 566dbb0d94cc3a18bd12179e60e57943ed28f3ac
  1. .travis.yml
  2. LICENSE
  3. README.md
  4. leveldb/
  5. manualtest/
README.md

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

Build Status

Installation

go get github.com/syndtr/goleveldb/leveldb

Requirements

  • Need at least go1.4 or newer.

Usage

Create or open a database:

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.