From ff22c97d9964790ac3aa34b7b6a3356edd0644aa Mon Sep 17 00:00:00 2001
From: shenglian zhou <slzhou@taosdata.com>
Date: Fri, 19 Aug 2022 08:39:19 +0800
Subject: [PATCH] fix: user tags scan filter produces zero row will not end the
 sys table scan operator

---
 source/libs/executor/src/scanoperator.c | 34 ++++++++++++++++++-------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/source/libs/executor/src/scanoperator.c b/source/libs/executor/src/scanoperator.c
index 7d188dadc7..5689b70824 100644
--- a/source/libs/executor/src/scanoperator.c
+++ b/source/libs/executor/src/scanoperator.c
@@ -2038,10 +2038,34 @@ static SSDataBlock* sysTableScanUserTags(SOperatorInfo* pOperator) {
     metaReaderClear(&smr);
 
     if (numOfRows >= pOperator->resultInfo.capacity) {
-      break;
+      p->info.rows = numOfRows;
+      pInfo->pRes->info.rows = numOfRows;
+
+      relocateColumnData(pInfo->pRes, pInfo->scanCols, p->pDataBlock, false);
+      doFilterResult(pInfo);
+
+      blockDataCleanup(p);
+      numOfRows = 0;
+
+      if (pInfo->pRes->info.rows > 0) {
+        break;
+      }
     }
   }
 
+  if (numOfRows > 0) {
+    p->info.rows = numOfRows;
+    pInfo->pRes->info.rows = numOfRows;
+
+    relocateColumnData(pInfo->pRes, pInfo->scanCols, p->pDataBlock, false);
+    doFilterResult(pInfo);
+
+    blockDataCleanup(p);
+    numOfRows = 0;
+  }
+
+  blockDataDestroy(p);
+
   // todo temporarily free the cursor here, the true reason why the free is not valid needs to be found
   if (ret != 0) {
     metaCloseTbCursor(pInfo->pCur);
@@ -2049,14 +2073,6 @@ static SSDataBlock* sysTableScanUserTags(SOperatorInfo* pOperator) {
     doSetOperatorCompleted(pOperator);
   }
 
-  p->info.rows = numOfRows;
-  pInfo->pRes->info.rows = numOfRows;
-
-  relocateColumnData(pInfo->pRes, pInfo->scanCols, p->pDataBlock, false);
-  doFilterResult(pInfo);
-
-  blockDataDestroy(p);
-
   pInfo->loadInfo.totalRows += pInfo->pRes->info.rows;
   return (pInfo->pRes->info.rows == 0) ? NULL : pInfo->pRes;
 }