diff --git a/lib/storage/partition.go b/lib/storage/partition.go
index ad5aaee2e7..82ea566174 100644
--- a/lib/storage/partition.go
+++ b/lib/storage/partition.go
@@ -1381,7 +1381,7 @@ func appendPartsToMerge(dst, src []*partWrapper, maxPartsToMerge int, maxRows ui
 	}
 	if maxM < minM {
 		// There is no sense in merging parts with too small m.
-		return dst, needFreeSpace
+		return dst, false
 	}
 	return append(dst, pws...), needFreeSpace
 }