diff --git a/source/libs/executor/src/scanoperator.c b/source/libs/executor/src/scanoperator.c
index b556733254ae96ae4c7aac2005bd5116d53d6846..94c5b2e0b7ac1542542ee769a831d0f6124ba2a7 100644
--- a/source/libs/executor/src/scanoperator.c
+++ b/source/libs/executor/src/scanoperator.c
@@ -1573,7 +1573,7 @@ static SSDataBlock* doQueueScan(SOperatorInfo* pOperator) {
         qError("submit msg messed up when initing stream submit block %p", pSubmit);
         pInfo->tqReader->pMsg = NULL;
         pTaskInfo->streamInfo.pReq = NULL;
-        ASSERT(0);
+        return NULL;
       }
     }
 
@@ -1628,11 +1628,14 @@ static SSDataBlock* doQueueScan(SOperatorInfo* pOperator) {
   if (pTaskInfo->streamInfo.prepareStatus.type == TMQ_OFFSET__LOG) {
     while (1) {
       SFetchRet ret = {0};
-      tqNextBlock(pInfo->tqReader, &ret);
+      if (tqNextBlock(pInfo->tqReader, &ret) < 0) {
+        qError("failed to get next log block since %s", terrstr());
+        return NULL;
+      }
       if (ret.fetchType == FETCH_TYPE__DATA) {
         blockDataCleanup(pInfo->pRes);
         if (setBlockIntoRes(pInfo, &ret.data, true) < 0) {
-          ASSERT(0);
+          return NULL;
         }
         if (pInfo->pRes->info.rows > 0) {
           pOperator->status = OP_EXEC_RECV;
@@ -1640,7 +1643,8 @@ static SSDataBlock* doQueueScan(SOperatorInfo* pOperator) {
           return pInfo->pRes;
         }
       } else if (ret.fetchType == FETCH_TYPE__META) {
-        ASSERT(0);
+        qError("unexpected ret.fetchType:%d", ret.fetchType);
+        return NULL;
         //        pTaskInfo->streamInfo.lastStatus = ret.offset;
         //        pTaskInfo->streamInfo.metaBlk = ret.meta;
         //        return NULL;
@@ -1667,7 +1671,7 @@ static SSDataBlock* doQueueScan(SOperatorInfo* pOperator) {
     return NULL;
 #endif
   } else {
-    ASSERT(0);
+    qError("unexpected streamInfo prepare type: %d", pTaskInfo->streamInfo.prepareStatus.type);
     return NULL;
   }
 }