func printRaftLogEntry(kv engine.MVCCKeyValue) (bool, error) {
	var meta engine.MVCCMetadata
	if err := meta.Unmarshal(kv.Value); err != nil {
		return false, err
	}
	value := roachpb.Value{
		RawBytes: meta.RawBytes,
	}
	var ent raftpb.Entry
	if err := value.GetProto(&ent); err != nil {
		return false, err
	}
	if len(ent.Data) > 0 {
		_, cmdData := storage.DecodeRaftCommand(ent.Data)
		var cmd roachpb.RaftCommand
		if err := cmd.Unmarshal(cmdData); err != nil {
			return false, err
		}
		ent.Data = nil
		fmt.Printf("%s\n", &ent)
		fmt.Printf("%s\n", &cmd)
	} else {
		fmt.Printf("%s: EMPTY\n", &ent)
	}
	return false, nil
}

// StoreData writes the supplied time series data to the cockroach server.
// Stored data will be sampled at the supplied resolution.
func (db *DB) StoreData(r Resolution, data []tspb.TimeSeriesData) error {
	var kvs []roachpb.KeyValue

	// Process data collection: data is converted to internal format, and a key
	// is generated for each internal message.
	for _, d := range data {
		idatas, err := d.ToInternal(r.KeyDuration(), r.SampleDuration())
		if err != nil {
			return err
		}
		for _, idata := range idatas {
			var value roachpb.Value
			if err := value.SetProto(&idata); err != nil {
				return err
			}
			kvs = append(kvs, roachpb.KeyValue{
				Key:   MakeDataKey(d.Name, d.Source, r, idata.StartTimestampNanos),
				Value: value,
			})
		}
	}

	// Send the individual internal merge requests.
	b := client.Batch{}
	for _, kv := range kvs {
		b.AddRawRequest(&roachpb.MergeRequest{
			Span: roachpb.Span{
				Key: kv.Key,
			},
			Value: kv.Value,
		})
	}

	return db.db.Run(&b)
}

func setAppliedIndex(
	ctx context.Context,
	eng engine.ReadWriter,
	ms *enginepb.MVCCStats,
	rangeID roachpb.RangeID,
	appliedIndex,
	leaseAppliedIndex uint64,
) error {
	var value roachpb.Value
	value.SetInt(int64(appliedIndex))

	if err := engine.MVCCPut(ctx, eng, ms,
		keys.RaftAppliedIndexKey(rangeID),
		hlc.ZeroTimestamp,
		value,
		nil /* txn */); err != nil {
		return err
	}
	value.SetInt(int64(leaseAppliedIndex))
	return engine.MVCCPut(ctx, eng, ms,
		keys.LeaseAppliedIndexKey(rangeID),
		hlc.ZeroTimestamp,
		value,
		nil /* txn */)
}

func setFrozenStatus(
	eng engine.ReadWriter, ms *enginepb.MVCCStats, rangeID roachpb.RangeID, frozen bool,
) error {
	var val roachpb.Value
	val.SetBool(frozen)
	return engine.MVCCPut(context.Background(), eng, ms,
		keys.RangeFrozenStatusKey(rangeID), hlc.ZeroTimestamp, val, nil)
}

// insertCPutFn is used by insertRow when conflicts should be respected.
// logValue is used for pretty printing.
func insertCPutFn(b *client.Batch, key *roachpb.Key, value *roachpb.Value) {
	// TODO(dan): We want do this V(2) log everywhere in sql. Consider making a
	// client.Batch wrapper instead of inlining it everywhere.
	if log.V(2) {
		log.InfofDepth(1, "CPut %s -> %s", *key, value.PrettyPrint())
	}
	b.CPut(key, value, nil)
}

// setLastIndex persists a new last index.
func setLastIndex(eng engine.Engine, rangeID roachpb.RangeID, lastIndex uint64) error {
	var value roachpb.Value
	value.SetInt(int64(lastIndex))

	return engine.MVCCPut(eng, nil, keys.RaftLastIndexKey(rangeID),
		roachpb.ZeroTimestamp,
		value,
		nil /* txn */)
}

func setLastIndex(eng engine.ReadWriter, rangeID roachpb.RangeID, lastIndex uint64) error {
	var value roachpb.Value
	value.SetInt(int64(lastIndex))

	return engine.MVCCPut(context.Background(), eng, nil, keys.RaftLastIndexKey(rangeID),
		hlc.ZeroTimestamp,
		value,
		nil /* txn */)
}

func maybeUnmarshalInline(v []byte, dest proto.Message) error {
	var meta enginepb.MVCCMetadata
	if err := meta.Unmarshal(v); err != nil {
		return err
	}
	value := roachpb.Value{
		RawBytes: meta.RawBytes,
	}
	return value.GetProto(dest)
}

// setAppliedIndex persists a new applied index.
func setAppliedIndex(eng engine.Engine, ms *engine.MVCCStats, rangeID roachpb.RangeID, appliedIndex uint64) error {
	var value roachpb.Value
	value.SetInt(int64(appliedIndex))

	return engine.MVCCPut(eng, ms,
		keys.RaftAppliedIndexKey(rangeID),
		roachpb.ZeroTimestamp,
		value,
		nil /* txn */)
}

// mustGetInt decodes an int64 value from the bytes field of the receiver
// and panics if the bytes field is not 0 or 8 bytes in length.
func mustGetInt(v *roachpb.Value) int64 {
	if v == nil {
		return 0
	}
	i, err := v.GetInt()
	if err != nil {
		panic(err)
	}
	return i
}

func newInfo(val float64) Info {
	now := timeutil.Now()

	v := roachpb.Value{Timestamp: hlc.Timestamp{WallTime: now.UnixNano()}}
	v.SetFloat(val)

	return Info{
		Value:     v,
		OrigStamp: now.UnixNano(),
		TTLStamp:  now.Add(time.Millisecond).UnixNano(),
	}
}

func writeRandomTimeSeriesDataToRange(
	t testing.TB,
	store *storage.Store,
	rangeID roachpb.RangeID,
	keyPrefix []byte,
) (midpoint []byte) {
	src := rand.New(rand.NewSource(0))
	r := ts.Resolution10s
	for i := 0; i < 20; i++ {
		var data []tspb.TimeSeriesData
		for j := int64(0); j <= src.Int63n(5); j++ {
			d := tspb.TimeSeriesData{
				Name:   "test.random.metric",
				Source: "cpu01",
			}
			for k := int64(0); k <= src.Int63n(10); k++ {
				d.Datapoints = append(d.Datapoints, tspb.TimeSeriesDatapoint{
					TimestampNanos: src.Int63n(200) * r.KeyDuration(),
					Value:          src.Float64(),
				})
			}
			data = append(data, d)
		}
		for _, d := range data {
			idatas, err := d.ToInternal(r.KeyDuration(), r.SampleDuration())
			if err != nil {
				t.Fatal(err)
			}
			for _, idata := range idatas {
				var value roachpb.Value
				if err := value.SetProto(&idata); err != nil {
					t.Fatal(err)
				}
				mArgs := roachpb.MergeRequest{
					Span: roachpb.Span{
						Key: encoding.EncodeVarintAscending(keyPrefix, idata.StartTimestampNanos),
					},
					Value: value,
				}
				if _, pErr := client.SendWrappedWith(rg1(store), nil, roachpb.Header{
					RangeID: rangeID,
				}, &mArgs); pErr != nil {
					t.Fatal(pErr)
				}
			}
		}
	}
	// Return approximate midway point (100 is midway between random timestamps in range [0,200)).
	midKey := append([]byte(nil), keyPrefix...)
	midKey = encoding.EncodeVarintAscending(midKey, 100*r.KeyDuration())
	return keys.MakeRowSentinelKey(midKey)
}

// Create the key/value pairs for the default zone config entry.
func createDefaultZoneConfig() []roachpb.KeyValue {
	var ret []roachpb.KeyValue
	value := roachpb.Value{}
	desc := config.DefaultZoneConfig()
	if err := value.SetProto(&desc); err != nil {
		log.Fatalf("could not marshal %v", desc)
	}
	ret = append(ret, roachpb.KeyValue{
		Key:   MakeZoneKey(keys.RootNamespaceID),
		Value: value,
	})
	return ret
}

func newInfo(val float64) info {
	now := time.Now()

	v := roachpb.Value{Timestamp: &roachpb.Timestamp{WallTime: now.UnixNano()}}
	v.SetFloat(val)

	return info{
		Info: Info{
			Value:    v,
			TTLStamp: now.Add(time.Millisecond).UnixNano(),
		},
	}
}

// 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(roachpb.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([]roachpb.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] = roachpb.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 := roachpb.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
}

// storeGossipUpdate is the gossip callback used to keep the StorePool up to date.
func (sp *StorePool) storeGossipUpdate(_ string, content roachpb.Value) {
	var storeDesc roachpb.StoreDescriptor
	if err := content.GetProto(&storeDesc); err != nil {
		log.Error(context.TODO(), err)
		return
	}

	sp.mu.Lock()
	defer sp.mu.Unlock()
	// Does this storeDetail exist yet?
	detail := sp.getStoreDetailLocked(storeDesc.StoreID)
	detail.markAlive(sp.clock.Now(), &storeDesc)
	sp.mu.queue.enqueue(detail)
}

func tryMeta(kv engine.MVCCKeyValue) (string, error) {
	if !bytes.HasPrefix(kv.Key.Key, keys.Meta1Prefix) && !bytes.HasPrefix(kv.Key.Key, keys.Meta2Prefix) {
		return "", errors.New("not a meta key")
	}
	value := roachpb.Value{
		Timestamp: kv.Key.Timestamp,
		RawBytes:  kv.Value,
	}
	var desc roachpb.RangeDescriptor
	if err := value.GetProto(&desc); err != nil {
		return "", err
	}
	return descStr(desc), nil
}

// PutSequence writes a sequence number for the specified family.
func (rc *ResponseCache) PutSequence(e engine.Engine, family []byte, sequence int64, err error) error {
	if sequence <= 0 || len(family) == 0 {
		return errEmptyID
	}
	if !rc.shouldCacheError(err) {
		return nil
	}

	// Write the response value to the engine.
	key := keys.ResponseCacheKey(rc.rangeID, family)
	var v roachpb.Value
	v.SetInt(sequence)
	return engine.MVCCPut(e, nil /* ms */, key, roachpb.ZeroTimestamp, v, nil /* txn */)
}

// BenchmarkMVCCMergeTimeSeries computes performance of merging time series data.
func BenchmarkMVCCMergeTimeSeries(b *testing.B) {
	ts := &roachpb.InternalTimeSeriesData{
		StartTimestampNanos: 0,
		SampleDurationNanos: 1000,
		Samples: []*roachpb.InternalTimeSeriesSample{
			{Offset: 0, Count: 1, Sum: 5.0},
		},
	}
	var value roachpb.Value
	if err := value.SetProto(ts); err != nil {
		b.Fatal(err)
	}
	runMVCCMerge(&value, 1024, b)
}

// append the given entries to the raft log. Takes the previous values of
// r.mu.lastIndex and r.mu.raftLogSize, and returns new values. We do this
// rather than modifying them directly because these modifications need to be
// atomic with the commit of the batch.
func (r *Replica) append(
	ctx context.Context,
	batch engine.ReadWriter,
	prevLastIndex uint64,
	prevRaftLogSize int64,
	entries []raftpb.Entry,
) (uint64, int64, error) {
	if len(entries) == 0 {
		return prevLastIndex, prevRaftLogSize, nil
	}
	var diff enginepb.MVCCStats
	var value roachpb.Value
	for i := range entries {
		ent := &entries[i]
		key := keys.RaftLogKey(r.RangeID, ent.Index)
		if err := value.SetProto(ent); err != nil {
			return 0, 0, err
		}
		value.InitChecksum(key)
		var err error
		if ent.Index > prevLastIndex {
			err = engine.MVCCBlindPut(ctx, batch, &diff, key, hlc.ZeroTimestamp, value, nil /* txn */)
		} else {
			err = engine.MVCCPut(ctx, batch, &diff, key, hlc.ZeroTimestamp, value, nil /* txn */)
		}
		if err != nil {
			return 0, 0, err
		}
	}

	// Delete any previously appended log entries which never committed.
	lastIndex := entries[len(entries)-1].Index
	for i := lastIndex + 1; i <= prevLastIndex; i++ {
		err := engine.MVCCDelete(ctx, batch, &diff, keys.RaftLogKey(r.RangeID, i),
			hlc.ZeroTimestamp, nil /* txn */)
		if err != nil {
			return 0, 0, err
		}
	}

	if err := setLastIndex(ctx, batch, r.RangeID, lastIndex); err != nil {
		return 0, 0, err
	}

	raftLogSize := prevRaftLogSize + diff.SysBytes

	return lastIndex, raftLogSize, nil
}