diff --git a/mvcc/index.go b/mvcc/index.go
index c9b0d1831..a88ef46e8 100644
--- a/mvcc/index.go
+++ b/mvcc/index.go
@@ -26,6 +26,7 @@ type index interface {
 	Get(key []byte, atRev int64) (rev, created revision, ver int64, err error)
 	Range(key, end []byte, atRev int64) ([][]byte, []revision)
 	Revisions(key, end []byte, atRev int64) []revision
+	CountRevisions(key, end []byte, atRev int64) int
 	Put(key []byte, rev revision)
 	Tombstone(key []byte, rev revision) error
 	RangeSince(key, end []byte, rev int64) []revision
@@ -119,6 +120,23 @@ func (ti *treeIndex) Revisions(key, end []byte, atRev int64) (revs []revision) {
 	return revs
 }
 
+func (ti *treeIndex) CountRevisions(key, end []byte, atRev int64) int {
+	if end == nil {
+		_, _, _, err := ti.Get(key, atRev)
+		if err != nil {
+			return 0
+		}
+		return 1
+	}
+	total := 0
+	ti.visit(key, end, func(ki *keyIndex) {
+		if _, _, _, err := ki.get(ti.lg, atRev); err == nil {
+			total++
+		}
+	})
+	return total
+}
+
 func (ti *treeIndex) Range(key, end []byte, atRev int64) (keys [][]byte, revs []revision) {
 	if end == nil {
 		rev, _, _, err := ti.Get(key, atRev)
diff --git a/mvcc/kvstore_test.go b/mvcc/kvstore_test.go
index 6d2e1aa20..ff858fc7c 100644
--- a/mvcc/kvstore_test.go
+++ b/mvcc/kvstore_test.go
@@ -941,6 +941,11 @@ func (i *fakeIndex) Revisions(key, end []byte, atRev int64) []revision {
 	return rev
 }
 
+func (i *fakeIndex) CountRevisions(key, end []byte, atRev int64) int {
+	_, rev := i.Range(key, end, atRev)
+	return len(rev)
+}
+
 func (i *fakeIndex) Get(key []byte, atRev int64) (rev, created revision, ver int64, err error) {
 	i.Recorder.Record(testutil.Action{Name: "get", Params: []interface{}{key, atRev}})
 	r := <-i.indexGetRespc
diff --git a/mvcc/kvstore_txn.go b/mvcc/kvstore_txn.go
index e89ddbee4..2b89dd50b 100644
--- a/mvcc/kvstore_txn.go
+++ b/mvcc/kvstore_txn.go
@@ -125,15 +125,16 @@ func (tr *storeTxnRead) rangeKeys(key, end []byte, curRev int64, ro RangeOptions
 	if rev < tr.s.compactMainRev {
 		return &RangeResult{KVs: nil, Count: -1, Rev: 0}, ErrCompacted
 	}
-
+	if ro.Count {
+		total := tr.s.kvindex.CountRevisions(key, end, rev)
+		tr.trace.Step("count revisions from in-memory index tree")
+		return &RangeResult{KVs: nil, Count: total, Rev: curRev}, nil
+	}
 	revpairs := tr.s.kvindex.Revisions(key, end, rev)
 	tr.trace.Step("range keys from in-memory index tree")
 	if len(revpairs) == 0 {
 		return &RangeResult{KVs: nil, Count: 0, Rev: curRev}, nil
 	}
-	if ro.Count {
-		return &RangeResult{KVs: nil, Count: len(revpairs), Rev: curRev}, nil
-	}
 
 	limit := int(ro.Limit)
 	if limit <= 0 || limit > len(revpairs) {