diff --git a/source/client/src/clientHb.c b/source/client/src/clientHb.c
index 7ce80553a0..75ccd44977 100644
--- a/source/client/src/clientHb.c
+++ b/source/client/src/clientHb.c
@@ -878,12 +878,18 @@ int hbMgrInit() {
   clientHbMgr.appHbMgrs = taosArrayInit(0, sizeof(void *));
 
   TdThreadMutexAttr attr = {0};
-  taosThreadMutexAttrSetType(&attr, PTHREAD_MUTEX_RECURSIVE);
+
   int ret = taosThreadMutexAttrInit(&attr);
   assert(ret == 0);
 
-  taosThreadMutexInit(&clientHbMgr.lock, &attr);
-  taosThreadMutexAttrDestroy(&attr);
+  ret = taosThreadMutexAttrSetType(&attr, PTHREAD_MUTEX_RECURSIVE);
+  assert(ret == 0);
+
+  ret = taosThreadMutexInit(&clientHbMgr.lock, &attr);
+  assert(ret == 0);
+
+  ret = taosThreadMutexAttrDestroy(&attr);
+  assert(ret == 0);
 
   // init handle funcs
   hbMgrInitHandle();
diff --git a/source/common/src/tdatablock.c b/source/common/src/tdatablock.c
index 16b8e55cf7..8a8e6a83a5 100644
--- a/source/common/src/tdatablock.c
+++ b/source/common/src/tdatablock.c
@@ -1446,6 +1446,7 @@ size_t blockDataGetCapacityInRow(const SSDataBlock* pBlock, size_t pageSize) {
   int32_t payloadSize = pageSize - blockDataGetSerialMetaSize(numOfCols);
   int32_t rowSize = pBlock->info.rowSize;
   int32_t nRows = payloadSize / rowSize;
+  ASSERT(nRows >= 1);
 
   // the true value must be less than the value of nRows
   int32_t additional = 0;
diff --git a/source/dnode/vnode/src/tsdb/tsdbMergeTree.c b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
index 45fe29f0fa..5f03a82bc0 100644
--- a/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
+++ b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
@@ -320,6 +320,7 @@ void tLDataIterNextBlock(SLDataIter *pIter) {
 
   pIter->pSttBlk = NULL;
   if (index != -1) {
+    pIter->iSttBlk = index;
     pIter->pSttBlk = (SSttBlk *)taosArrayGet(pIter->pBlockLoadInfo->aSttBlk, pIter->iSttBlk);
   }
 }
diff --git a/source/libs/executor/src/executil.c b/source/libs/executor/src/executil.c
index d75f0580e1..b88589740d 100644
--- a/source/libs/executor/src/executil.c
+++ b/source/libs/executor/src/executil.c
@@ -989,7 +989,8 @@ SArray* extractColMatchInfo(SNodeList* pNodeList, SDataBlockDescNode* pOutputNod
 
     if (pNode->output) {
       (*numOfOutputCols) += 1;
-    } else {
+    } else if (info != NULL) {
+      // select distinct tbname from stb where tbname='abc';
       info->output = false;
     }
   }
diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c
index 9b502eded7..a23f58a732 100644
--- a/source/libs/function/src/builtinsimpl.c
+++ b/source/libs/function/src/builtinsimpl.c
@@ -5297,12 +5297,12 @@ bool modeFunctionSetup(SqlFunctionCtx* pCtx, SResultRowEntryInfo* pResInfo) {
 }
 
 static void doModeAdd(SModeInfo* pInfo, char* data) {
-  int32_t     hashKeyBytes = IS_VAR_DATA_TYPE(pInfo->colType) ? varDataTLen(data) : pInfo->colBytes;
+  int32_t     hashKeyBytes = IS_STR_DATA_TYPE(pInfo->colType) ? varDataTLen(data) : pInfo->colBytes;
   SModeItem** pHashItem = taosHashGet(pInfo->pHash, data, hashKeyBytes);
   if (pHashItem == NULL) {
     int32_t    size = sizeof(SModeItem) + pInfo->colBytes;
     SModeItem* pItem = (SModeItem*)(pInfo->pItems + pInfo->numOfPoints * size);
-    memcpy(pItem->data, data, pInfo->colBytes);
+    memcpy(pItem->data, data, hashKeyBytes);
     pItem->count += 1;
 
     taosHashPut(pInfo->pHash, data, hashKeyBytes, &pItem, sizeof(SModeItem*));