diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index a130a6e7ca3b7898189f20e2ddd57b1a42a585c9..814908a9b321cfec6cd7b6fe6377693647532ad7 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -1282,11 +1282,8 @@ static void doHashGroupbyAgg(SOperatorInfo* pOperator, SGroupbyOperatorInfo *pIn
     return;
   }
 
-  int64_t* tsList = NULL;
   SColumnInfoData* pFirstColData = taosArrayGet(pSDataBlock->pDataBlock, 0);
-  if (pFirstColData->info.type == TSDB_DATA_TYPE_TIMESTAMP) {
-    tsList = (int64_t*) pFirstColData->pData;
-  }
+  int64_t* tsList = (pFirstColData->info.type == TSDB_DATA_TYPE_TIMESTAMP)? (int64_t*) pFirstColData->pData:NULL;
 
   STimeWindow w = TSWINDOW_INITIALIZER;
 
@@ -1319,12 +1316,10 @@ static void doHashGroupbyAgg(SOperatorInfo* pOperator, SGroupbyOperatorInfo *pIn
     }
 
     if (pQueryAttr->stableQuery && pQueryAttr->stabledev && (pRuntimeEnv->prevResult != NULL)) {
-      setParamForStableStddevByColData(pRuntimeEnv, pInfo->binfo.pCtx, pOperator->numOfOutput, pOperator->pExpr, pInfo->prevData,
-                                       bytes);
+      setParamForStableStddevByColData(pRuntimeEnv, pInfo->binfo.pCtx, pOperator->numOfOutput, pOperator->pExpr, pInfo->prevData, bytes);
     }
 
-    int32_t ret = setGroupResultOutputBuf(pRuntimeEnv, &(pInfo->binfo), pOperator->numOfOutput, pInfo->prevData, type, bytes,
-                                          item->groupIndex);
+    int32_t ret = setGroupResultOutputBuf(pRuntimeEnv, &(pInfo->binfo), pOperator->numOfOutput, pInfo->prevData, type, bytes, item->groupIndex);
     if (ret != TSDB_CODE_SUCCESS) {  // null data, too many state code
       longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_APP_ERROR);
     }
@@ -1340,17 +1335,16 @@ static void doHashGroupbyAgg(SOperatorInfo* pOperator, SGroupbyOperatorInfo *pIn
     memcpy(pInfo->prevData, val, bytes);
 
     if (pQueryAttr->stableQuery && pQueryAttr->stabledev && (pRuntimeEnv->prevResult != NULL)) {
-      setParamForStableStddevByColData(pRuntimeEnv, pInfo->binfo.pCtx, pOperator->numOfOutput, pOperator->pExpr, val,
-                                       bytes);
+      setParamForStableStddevByColData(pRuntimeEnv, pInfo->binfo.pCtx, pOperator->numOfOutput, pOperator->pExpr, val, bytes);
     }
 
-    int32_t ret = setGroupResultOutputBuf(pRuntimeEnv, &(pInfo->binfo), pOperator->numOfOutput, val, type, bytes,
-                                          item->groupIndex);
+    int32_t ret = setGroupResultOutputBuf(pRuntimeEnv, &(pInfo->binfo), pOperator->numOfOutput, val, type, bytes, item->groupIndex);
     if (ret != TSDB_CODE_SUCCESS) {  // null data, too many state code
       longjmp(pRuntimeEnv->env, TSDB_CODE_QRY_APP_ERROR);
     }
 
     doApplyFunctions(pRuntimeEnv, pInfo->binfo.pCtx, &w, pSDataBlock->info.rows - num, num, tsList, pSDataBlock->info.rows, pOperator->numOfOutput);
+    tfree(pInfo->prevData);
   }
 }
 
diff --git a/tests/script/general/parser/groupby.sim b/tests/script/general/parser/groupby.sim
index 507431f536cac84d61a18d9c599e6bf9d344766d..6ae5d420d878c462477aa41c245d146dba95ce5e 100644
--- a/tests/script/general/parser/groupby.sim
+++ b/tests/script/general/parser/groupby.sim
@@ -741,4 +741,44 @@ if $data14 != 2 then
   return -1
 endi
 
+sql create table m1 (ts timestamp, k int, f1 int) tags(a int);
+sql create table tm0 using m1 tags(0);
+sql create table tm1 using m1 tags(1);
+
+sql insert into tm0 values('2020-1-1 1:1:1', 1, 10);
+sql insert into tm0 values('2020-1-1 1:1:2', 1, 20);
+sql insert into tm1 values('2020-2-1 1:1:1', 2, 10);
+sql insert into tm1 values('2020-2-1 1:1:2', 2, 20);
+
+system sh/exec.sh -n dnode1 -s stop -x SIGINT
+sleep 100
+system sh/exec.sh -n dnode1 -s start
+sleep 100
+
+sql connect
+sleep 100
+sql use group_db0;
+
+print =========================>TD-4894
+sql select count(*),k from m1 group by k;
+if $rows != 2 then
+  return -1
+endi
+
+if $data00 != 2 then
+  return -1
+endi
+
+if $data01 != 1 then
+  return -1
+endi
+
+if $data10 != 2 then
+  return -1
+endi
+
+if $data11 != 2 then
+  return -1
+endi
+
 system sh/exec.sh -n dnode1 -s stop -x SIGINT