Golang Value.InitChecksum方法代碼示例

// putInternal writes the specified value to key.
func (kv *KV) putInternal(key proto.Key, value proto.Value) error {
	value.InitChecksum(key)
	return kv.Call(proto.Put, &proto.PutRequest{
		RequestHeader: proto.RequestHeader{Key: key},
		Value:         value,
	}, &proto.PutResponse{})
}

// PutProto sets the given key to the protobuf-serialized byte string
// of msg and the provided timestamp.
func (mvcc *MVCC) PutProto(key Key, timestamp proto.Timestamp, txn *proto.Transaction, msg gogoproto.Message) error {
	data, err := gogoproto.Marshal(msg)
	if err != nil {
		return err
	}
	value := proto.Value{Bytes: data}
	value.InitChecksum(key)
	return mvcc.Put(key, timestamp, value, txn)
}

// PreparePutProto sets the given key to the protobuf-serialized byte
// string of msg. The resulting Put call is buffered and will not be
// sent until a subsequent call to Flush. Returns marshalling errors
// if encountered.
func (kv *KV) PreparePutProto(key proto.Key, msg gogoproto.Message) error {
	data, err := gogoproto.Marshal(msg)
	if err != nil {
		return err
	}
	value := proto.Value{Bytes: data}
	value.InitChecksum(key)
	kv.Prepare(proto.Put, &proto.PutRequest{
		RequestHeader: proto.RequestHeader{Key: key},
		Value:         value,
	}, &proto.PutResponse{})
	return nil
}

// setupMVCCData writes up to numVersions values at each of numKeys
// keys. The number of versions written for each key is chosen
// randomly according to a uniform distribution. Each successive
// version is written starting at 5ns and then in 5ns increments. This
// allows scans at various times, starting at t=5ns, and continuing to
// t=5ns*(numVersions+1). A version for each key will be read on every
// such scan, but the dynamics of the scan will change depending on
// the historical timestamp. Earlier timestamps mean scans which must
// skip more historical versions; later timestamps mean scans which
// skip fewer.
//
// The creation of the rocksdb database is time consuming, especially
// for larger numbers of versions. The database is persisted between
// runs and stored in the current directory as
// "mvcc_scan_<versions>_<keys>".
func setupMVCCScanData(numVersions, numKeys int, b *testing.B) (*RocksDB, *stop.Stopper) {
	loc := fmt.Sprintf("mvcc_scan_%d_%d", numVersions, numKeys)

	exists := true
	if _, err := os.Stat(loc); os.IsNotExist(err) {
		exists = false
	}

	log.Infof("creating mvcc data: %s", loc)
	const cacheSize = 8 << 30 // 8 GB
	stopper := stop.NewStopper()
	rocksdb := NewRocksDB(proto.Attributes{Attrs: []string{"ssd"}}, loc, cacheSize, stopper)
	if err := rocksdb.Open(); err != nil {
		b.Fatalf("could not create new rocksdb db instance at %s: %v", loc, err)
	}

	if exists {
		return rocksdb, stopper
	}

	rng, _ := randutil.NewPseudoRand()
	keys := make([]proto.Key, numKeys)
	nvs := make([]int, numKeys)
	for t := 1; t <= numVersions; t++ {
		walltime := int64(5 * t)
		ts := makeTS(walltime, 0)
		batch := rocksdb.NewBatch()
		for i := 0; i < numKeys; i++ {
			if t == 1 {
				keys[i] = proto.Key(encoding.EncodeUvarint([]byte("key-"), uint64(i)))
				nvs[i] = int(rand.Int31n(int32(numVersions)) + 1)
			}
			// Only write values if this iteration is less than the random
			// number of versions chosen for this key.
			if t <= nvs[i] {
				value := proto.Value{Bytes: randutil.RandBytes(rng, 1024)}
				value.InitChecksum(keys[i])
				if err := MVCCPut(batch, nil, keys[i], ts, value, nil); err != nil {
					b.Fatal(err)
				}
			}
		}
		if err := batch.Commit(); err != nil {
			b.Fatal(err)
		}
		batch.Close()
	}
	rocksdb.CompactRange(nil, nil)

	return rocksdb, stopper
}