diff --git a/source/dnode/vnode/src/tsdb/tsdbUtil.c b/source/dnode/vnode/src/tsdb/tsdbUtil.c
index 7d1cca37b5b020bd753e25cfd4dac4a469b5634c..0e2fb4b6aa031868b3c2859c2efc0a81372eb552 100644
--- a/source/dnode/vnode/src/tsdb/tsdbUtil.c
+++ b/source/dnode/vnode/src/tsdb/tsdbUtil.c
@@ -722,6 +722,7 @@ int32_t tsdbRowMergerAdd(SRowMerger *pMerger, TSDBROW *pRow, STSchema *pTSchema)
 
   if (taosArrayGetSize(pMerger->pArray) == 0) {
     // ts
+    jCol = 0;
     pTColumn = &pTSchema->columns[jCol++];
 
     ASSERT(pTColumn->type == TSDB_DATA_TYPE_TIMESTAMP);