diff --git a/source/dnode/vnode/src/tsdb/tsdbCache.c b/source/dnode/vnode/src/tsdb/tsdbCache.c
index b3a5cd129e..05c941cc4d 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCache.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCache.c
@@ -590,7 +590,10 @@ static int32_t getNextRowFromFS(void *iter, TSDBROW **ppRow) {
         goto _next_fileset;
       }
 
-      tMapDataReset(&state->blockMap);
+      if (state->blockMap.pData != NULL) {
+        tMapDataClear(&state->blockMap);
+      }
+
       code = tsdbReadDataBlk(state->pDataFReader, state->pBlockIdx, &state->blockMap);
       if (code) goto _err;
 
@@ -695,6 +698,10 @@ int32_t clearNextRowFromFS(void *iter) {
     state->pBlockData = NULL;
   }
 
+  if (state->blockMap.pData != NULL) {
+    tMapDataClear(&state->blockMap);
+  }
+
   return code;
 }