keydb

high performance key value database written in Go

bulk insert and sequential read < 3 micro secs

random access read of disk based record, approx. 13 us

uses LSM trees, see https://en.wikipedia.org/wiki/Log-structured_merge-tree

limitation of max 1024 byte keys, to allow efficient on disk index searching, but has compressed keys which allows for very efficient storage of time series data (market tick data) in the same table

use the dbdump and dbload utilities to save/restore databases to a single file, but just zipping up the directory works as well...

see the related http://github.com/robaho/keydbr which allows remote access to a keydb instance, and allows a keydb database to be shared by multiple processes

TODOs

make some settings configurable

purge removed key/value, it currently stores an empty []byte

How To Use

db, err := keydb.Open("test/mydb", true)
if err != nil {
	t.Fatal("unable to create database", err)
}
tx, err := db.BeginTX("main")
if err != nil {
	t.Fatal("unable to create transaction", err)
}
err = tx.Put([]byte("mykey"), []byte("myvalue"))
if err != nil {
	t.Fatal("unable to put key/Value", err)
}
err = tx.Commit()
if err != nil {
    t.Fatal("unable to commit transaction", err)
}
err = db.Close()
if err != nil {
    t.Fatal("unable to close database", err)
}

Performance

Using example/performance.go

insert time  1000000 records =  2836 ms, usec per op  2
close time  4028 ms
scan time  2476 ms, usec per op  2
scan time 50%  1146 ms, usec per op  2
random access time  15 us per get
close with merge 1 time  2 ms
scan time  2497 ms, usec per op  2
scan time 50%  1144 ms, usec per op  2
random access time  14 us per get