README
¶
Results of benchmarking
Using RocksDB
So, reading times are on the order of single unit microseconds, while writing
times with Sync set to true are ~30 milliseconds.
$ go test -run BenchmarkSet -v -bench .
PASS
BenchmarkGet_valsize100-6 500000 2850 ns/op
--- BENCH: BenchmarkGet_valsize100-6
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
BenchmarkGet_valsize1000-6 500000 3565 ns/op
--- BENCH: BenchmarkGet_valsize1000-6
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
BenchmarkGet_valsize10000-6 200000 8541 ns/op
--- BENCH: BenchmarkGet_valsize10000-6
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
store_test.go:85: Wrote 100 keys.
BenchmarkSet_valsize100-6 50 32932578 ns/op
BenchmarkSet_valsize1000-6 50 28066678 ns/op
BenchmarkSet_valsize10000-6 50 28736228 ns/op
ok github.com/dgraph-io/dgraph/store 48.393s
Also based on dgraph-io/experiments/db:
BoltDB
Without copying the resulting byte slice from Bolt. Unsafe
$ go test -bench BenchmarkRead .
testing: warning: no tests to run
PASS
BenchmarkReadBolt_1024 500000 3858 ns/op
BenchmarkReadBolt_10KB 500000 3738 ns/op
BenchmarkReadBolt_500KB 1000000 3141 ns/op
BenchmarkReadBolt_1MB 1000000 3026 ns/op
ok github.com/dgraph-io/experiments/db 102.513s
Copying the resulting byte slice. Safe
$ go test -bench BenchmarkRead .
testing: warning: no tests to run
PASS
BenchmarkReadBolt_1024 200000 6760 ns/op
BenchmarkReadBolt_10KB 100000 21249 ns/op
BenchmarkReadBolt_500KB 10000 214449 ns/op
BenchmarkReadBolt_1MB 3000 350712 ns/op
ok github.com/dgraph-io/experiments/db 80.890s
RocksDB
$ go test -bench BenchmarkGet .
PASS
BenchmarkGet_valsize1024 300000 5715 ns/op
BenchmarkGet_valsize10KB 50000 27619 ns/op
BenchmarkGet_valsize500KB 2000 604185 ns/op
BenchmarkGet_valsize1MB 2000 1064685 ns/op
ok github.com/dgraph-io/dgraph/store 55.029s
Thoughts
Dgraph uses append only commit log to sync new mutations to disk before returning. Every time a posting list gets init, it checks for both the stored posting list and the mutations committed after the posting list was written. Hence, our access pattern from store is largely read-only, with fewer writes. This is true, irrespective of how many writes get commited by the end user.
Hence, BoltDB is a better choice. It performs better for reads/seeks, despite Dgraph needing a value copy. Writes are somewhat slower, but that shouldn't be a problem because of the above mentioned reasons.
Update: Just realized that BoltDB only allows a SINGLE writer at any point in time. This is equivalent to a global mutex lock. That'd essentially kill Dgraph's performance. So, BoltDB is out!
Documentation
¶
Index ¶
- type Store
- func (s *Store) Close()
- func (s *Store) Delete(k []byte) error
- func (s *Store) Get(key []byte) (val []byte, rerr error)
- func (s *Store) GetIterator() *rocksdb.Iterator
- func (s *Store) IndexFilterblockSize() uint64
- func (s *Store) Init(filepath string) (err error)
- func (s *Store) InitReadOnly(filepath string) (err error)
- func (s *Store) MemtableSize() uint64
- func (s *Store) SetOne(k []byte, val []byte) error
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Store ¶
type Store struct {
// contains filtered or unexported fields
}
Source Files