Merge pull request #125 from cockroachdb/spencerkimball/stat-counters

Flush MVCC stats to range and store counters.

storage/engine/keys.go

@@ -207,12 +207,56 @@ func ValidateRangeMetaKey(key Key) error {
 	return nil
 }
 
+// MakeRangeStatKey returns the key for accessing the named stat
+// for the specified range ID.
+func MakeRangeStatKey(rangeID int64, stat Key) Key {
+	encRangeID := encoding.EncodeInt(nil, rangeID)
+	return MakeKey(KeyLocalRangeStatPrefix, encRangeID, stat)
+}
+
+// MakeStoreStatKey returns the key for accessing the named stat
+// for the specified store ID.
+func MakeStoreStatKey(storeID int32, stat Key) Key {
+	encStoreID := encoding.EncodeInt(nil, int64(storeID))
+	return MakeKey(KeyLocalStoreStatPrefix, encStoreID, stat)
+}
+
 func init() {
 	if KeyLocalPrefixLength%7 != 0 {
 		log.Fatal("local key prefix is not a multiple of 7: %d", KeyLocalPrefixLength)
 	}
 }
 
+// Constants for key construction.
+var (
+	// StatLiveBytes counts how many bytes are "live", including bytes
+	// from both keys and values. Live rows include only non-deleted
+	// keys and only the most recent value.
+	StatLiveBytes = Key("live-bytes")
+	// StatKeyBytes counts how many bytes are used to store all keys,
+	// including bytes from deleted keys. Key bytes are re-counted for
+	// each versioned value.
+	StatKeyBytes = Key("key-bytes")
+	// StatValBytes counts how many bytes are used to store all values,
+	// including all historical versions and deleted tombstones.
+	StatValBytes = Key("val-bytes")
+	// StatIntentBytes counts how many bytes are used to store values
+	// which are unresolved intents. Includes bytes used for both intent
+	// keys and values.
+	StatIntentBytes = Key("intent-bytes")
+	// StatLiveCount counts how many keys are "live". This includes only
+	// non-deleted keys.
+	StatLiveCount = Key("live-count")
+	// StatKeyCount counts the total number of keys, including both live
+	// and deleted keys.
+	StatKeyCount = Key("key-count")
+	// StatValCount counts the total number of values, including all
+	// historical versions and deleted tombstones.
+	StatValCount = Key("val-count")
+	// StatIntentCount counts the number of unresolved intents.
+	StatIntentCount = Key("intent-count")
+)
+
 // Constants for system-reserved keys in the KV map.
 var (
 	// KeyMaxLength is the maximum key length in bytes. This value is
@@ -263,15 +307,15 @@ var (
 	// KeyLocalRangeMetadataPrefix is the prefix for keys storing range metadata.
 	// The value is a struct of type RangeMetadata.
 	KeyLocalRangeMetadataPrefix = MakeKey(KeyLocalPrefix, Key("rng-"))
+	// KeyLocalRangeStatPrefix is the prefix for range statistics.
+	KeyLocalRangeStatPrefix = MakeKey(KeyLocalPrefix, Key("rst-"))
 	// KeyLocalResponseCachePrefix is the prefix for keys storing command
-	// responses used to guarantee idempotency (see ResponseCache). This key
-	// prefix is duplicated in rocksdb_compaction.cc and must be kept in sync
-	// if modified here.
+	// responses used to guarantee idempotency (see ResponseCache).
 	KeyLocalResponseCachePrefix = MakeKey(KeyLocalPrefix, Key("res-"))
+	// KeyLocalStoreStatPrefix is the prefix for store statistics.
+	KeyLocalStoreStatPrefix = MakeKey(KeyLocalPrefix, Key("sst-"))
 	// KeyLocalTransactionPrefix specifies the key prefix for
-	// transaction records. The suffix is the transaction id. This key
-	// prefix is duplicated in rocksdb_compaction.cc and must be kept in
-	// sync if modified here.
+	// transaction records. The suffix is the transaction id.
 	KeyLocalTransactionPrefix = MakeKey(KeyLocalPrefix, Key("txn-"))
 	// KeyLocalSnapshotIDGenerator is a snapshot ID generator sequence.
 	// Snapshot IDs must be unique per store ID.

storage/engine/mvcc.go

@@ -34,6 +34,21 @@ const (
 	splitReservoirSize = 100
 )
 
+// encodeMVCCStatValue constructs a proto.Value using the supplied
+// stat increment and then encodes that into a byte slice. Encoding
+// errors cause panics (as they should never happen). Returns false
+// if stat is equal to 0 to avoid unnecessary merge.
+func encodeMVCCStatValue(stat int64) (ok bool, enc []byte) {
+	if stat == 0 {
+		return false, nil
+	}
+	data, err := gogoproto.Marshal(&proto.Value{Integer: gogoproto.Int64(stat)})
+	if err != nil {
+		panic(fmt.Sprintf("could not marshal proto.Value: %s", err))
+	}
+	return true, data
+}
+
 // MVCCStats tracks byte and instance counts for:
 //  - Live key/values (i.e. what a scan at current time will reveal;
 //    note that this includes intent keys and values, but not keys and
@@ -612,6 +627,28 @@ func (mvcc *MVCC) ResolveWriteIntentRange(key, endKey Key, max int64, txn *proto
 	return num, nil
 }
 
+// FlushStat flushes the specified stat to merge counters for both
+// the affected range and store.
+func (mvcc *MVCC) FlushStat(rangeID int64, storeID int32, stat Key, statVal int64) {
+	if ok, encStat := encodeMVCCStatValue(statVal); ok {
+		mvcc.batch.Merge(MakeRangeStatKey(rangeID, stat), encStat)
+		mvcc.batch.Merge(MakeStoreStatKey(storeID, stat), encStat)
+	}
+}
+
+// FlushStats flushes stats to merge counters for both the affected
+// range and store.
+func (mvcc *MVCC) FlushStats(rangeID int64, storeID int32) {
+	mvcc.FlushStat(rangeID, storeID, StatLiveBytes, mvcc.LiveBytes)
+	mvcc.FlushStat(rangeID, storeID, StatKeyBytes, mvcc.KeyBytes)
+	mvcc.FlushStat(rangeID, storeID, StatValBytes, mvcc.ValBytes)
+	mvcc.FlushStat(rangeID, storeID, StatIntentBytes, mvcc.IntentBytes)
+	mvcc.FlushStat(rangeID, storeID, StatLiveCount, mvcc.LiveCount)
+	mvcc.FlushStat(rangeID, storeID, StatKeyCount, mvcc.KeyCount)
+	mvcc.FlushStat(rangeID, storeID, StatValCount, mvcc.ValCount)
+	mvcc.FlushStat(rangeID, storeID, StatIntentCount, mvcc.IntentCount)
+}
+
 // a splitSampleItem wraps a key along with an aggregate over key range
 // preceding it.
 type splitSampleItem struct {

storage/range.go

@@ -678,14 +678,14 @@ func (r *Range) executeCmd(method string, args proto.Request, reply proto.Respon
 		return util.Errorf("unrecognized command type: %s", method)
 	}
 
-	// Commit the batch on success.
-	if reply.Header().Error == nil {
+	// On success, flush the MVCC stats to the batch and commit.
+	if !IsReadOnly(method) && reply.Header().Error == nil {
+		mvcc.FlushStats(r.Meta.RangeID, r.rm.StoreID())
 		reply.Header().SetGoError(batch.Commit())
 	}
 
 	// Maybe update gossip configs on a put if there was no error.
-	if (method == Put || method == ConditionalPut) &&
-		reply.Header().Error == nil {
+	if (method == Put || method == ConditionalPut) && reply.Header().Error == nil {
 		r.maybeUpdateGossipConfigs(args.Header().Key)
 	}
 

storage/range_test.go

@@ -355,6 +355,18 @@ func putArgs(key, value []byte, rangeID int64) (*proto.PutRequest, *proto.PutRes
 	return args, reply
 }
 
+// deleteArgs returns a DeleteRequest and DeleteResponse pair.
+func deleteArgs(key engine.Key, rangeID int64) (*proto.DeleteRequest, *proto.DeleteResponse) {
+	args := &proto.DeleteRequest{
+		RequestHeader: proto.RequestHeader{
+			Key:     key,
+			Replica: proto.Replica{RangeID: rangeID},
+		},
+	}
+	reply := &proto.DeleteResponse{}
+	return args, reply
+}
+
 // readOrWriteArgs returns either get or put arguments depending on
 // value of "read". Get for true; Put for false. Returns method
 // selected and args & reply.
@@ -1403,3 +1415,84 @@ func TestInternalPushTxnPushTimestampAlreadyPushed(t *testing.T) {
 		t.Errorf("expected pushed txn to have status PENDING; got %s", reply.PusheeTxn.Status)
 	}
 }
+
+func verifyStatCounter(eng engine.Engine, rangeID int64, stat engine.Key, expVal int64, t *testing.T) {
+	statVal := &proto.Value{}
+	ok, err := engine.GetProto(eng, engine.MakeRangeStatKey(rangeID, stat), statVal)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if expVal == 0 && !ok {
+		return
+	} else if expVal != 0 && !ok {
+		t.Errorf("stat %q missing", stat)
+	}
+	if statVal.GetInteger() != expVal {
+		t.Errorf("expected stat %q to have value %d; got %d", stat, expVal, statVal.GetInteger())
+	}
+}
+
+func verifyRangeStats(eng engine.Engine, rangeID int64, expMS engine.MVCCStats, t *testing.T) {
+	verifyStatCounter(eng, rangeID, engine.StatLiveBytes, expMS.LiveBytes, t)
+	verifyStatCounter(eng, rangeID, engine.StatKeyBytes, expMS.KeyBytes, t)
+	verifyStatCounter(eng, rangeID, engine.StatValBytes, expMS.ValBytes, t)
+	verifyStatCounter(eng, rangeID, engine.StatIntentBytes, expMS.IntentBytes, t)
+	verifyStatCounter(eng, rangeID, engine.StatLiveCount, expMS.LiveCount, t)
+	verifyStatCounter(eng, rangeID, engine.StatKeyCount, expMS.KeyCount, t)
+	verifyStatCounter(eng, rangeID, engine.StatValCount, expMS.ValCount, t)
+	verifyStatCounter(eng, rangeID, engine.StatIntentCount, expMS.IntentCount, t)
+}
+
+// TestRangeStats verifies that commands executed against a range
+// update the range stat counters. The stat values are empirically
+// derived; we're really just testing that they increment in the right
+// ways, not the exact amounts. If the encodings change, will need to
+// update this test.
+func TestRangeStats(t *testing.T) {
+	rng, _, clock, eng := createTestRangeWithClock(t)
+	defer rng.Stop()
+	// Put a value.
+	pArgs, pReply := putArgs([]byte("a"), []byte("value1"), 0)
+	pArgs.Timestamp = clock.Now()
+	if err := rng.AddCmd(Put, pArgs, pReply, true); err != nil {
+		t.Fatal(err)
+	}
+	expMS := engine.MVCCStats{LiveBytes: 44, KeyBytes: 20, ValBytes: 24, IntentBytes: 0, LiveCount: 1, KeyCount: 1, ValCount: 1, IntentCount: 0}
+	verifyRangeStats(eng, rng.Meta.RangeID, expMS, t)
+
+	// Put a 2nd value transactionally.
+	pArgs, pReply = putArgs([]byte("b"), []byte("value2"), 0)
+	pArgs.Timestamp = clock.Now()
+	pArgs.Txn = &proto.Transaction{ID: []byte("txn1"), Timestamp: pArgs.Timestamp}
+	if err := rng.AddCmd(Put, pArgs, pReply, true); err != nil {
+		t.Fatal(err)
+	}
+	expMS = engine.MVCCStats{LiveBytes: 118, KeyBytes: 40, ValBytes: 78, IntentBytes: 28, LiveCount: 2, KeyCount: 2, ValCount: 2, IntentCount: 1}
+	verifyRangeStats(eng, rng.Meta.RangeID, expMS, t)
+
+	// Resolve the 2nd value.
+	rArgs := &proto.InternalResolveIntentRequest{
+		RequestHeader: proto.RequestHeader{
+			Timestamp: pArgs.Txn.Timestamp,
+			Key:       pArgs.Key,
+			Replica:   proto.Replica{RangeID: 0},
+			Txn:       pArgs.Txn,
+		},
+	}
+	rArgs.Txn.Status = proto.COMMITTED
+	rReply := &proto.InternalResolveIntentResponse{}
+	if err := rng.AddCmd(InternalResolveIntent, rArgs, rReply, true); err != nil {
+		t.Fatal(err)
+	}
+	expMS = engine.MVCCStats{LiveBytes: 88, KeyBytes: 40, ValBytes: 48, IntentBytes: 0, LiveCount: 2, KeyCount: 2, ValCount: 2, IntentCount: 0}
+	verifyRangeStats(eng, rng.Meta.RangeID, expMS, t)
+
+	// Delete the 1st value.
+	dArgs, dReply := deleteArgs([]byte("a"), 0)
+	dArgs.Timestamp = clock.Now()
+	if err := rng.AddCmd(Delete, dArgs, dReply, true); err != nil {
+		t.Fatal(err)
+	}
+	expMS = engine.MVCCStats{LiveBytes: 44, KeyBytes: 56, ValBytes: 50, IntentBytes: 0, LiveCount: 1, KeyCount: 2, ValCount: 3, IntentCount: 0}
+	verifyRangeStats(eng, rng.Meta.RangeID, expMS, t)
+}

storage/store.go

@@ -325,6 +325,7 @@ func (s *Store) BootstrapRangeMetadata() *proto.RangeMetadata {
 }
 
 // The following methods are accessors implementation the RangeManager interface.
+func (s *Store) StoreID() int32         { return s.Ident.StoreID }
 func (s *Store) Clock() *hlc.Clock      { return s.clock }
 func (s *Store) Engine() engine.Engine  { return s.engine }
 func (s *Store) Allocator() *allocator  { return s.allocator }
@@ -577,6 +578,7 @@ func (s *Store) maybeResolveWriteIntentError(rng *Range, method string, args pro
 // (i.e. splitting and merging) operations.
 type RangeManager interface {
 	// Accessors for shared state.
+	StoreID() int32
 	Clock() *hlc.Clock
 	Engine() engine.Engine
 	Allocator() *allocator