| commit | 1338fcd7ccafd81faad23486e22d14f1fad72229 | [log] [tgz] |
|---|---|---|
| author | Suryandaru Triandana <syndtr@gmail.com> | Thu Apr 02 12:29:39 2015 +0700 |
| committer | Suryandaru Triandana <syndtr@gmail.com> | Thu Apr 02 12:29:39 2015 +0700 |
| tree | 7fb654316f7a83355284b1821a2b79e79973d2d1 | |
| parent | 853c9132c51c79ee38121132fee6078474b841ee [diff] |
leveldb: allows iterator to trigger compaction This implements fix that was introduced in LevelDB 1.13, to fix issue where large contiguous keyspace of deleted data was not getting compacted. Reported at syncthing/syncthing#1480.
This is an implementation of the LevelDB key/value database in the Go programming language.
go get github.com/syndtr/goleveldb/leveldb
go1.2 or newer.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()
...
You can read package documentation here.