diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index f5b887936814b4d0614c9cb2ded71235e5863904..d2fb5d6a47a80a62fc68f3e9271d5fa7c8df0370 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -3362,13 +3362,7 @@ int32_t addExprAndResultField(SSqlCmd* pCmd, SQueryInfo* pQueryInfo, int32_t col
         tVariantDump(pVariant, val, TSDB_DATA_TYPE_BIGINT, true);
 
         if(functionId == TSDB_FUNC_UNIQUE){   // consider of memory size
-          if(pSchema->bytes < 10){
-            GET_INT64_VAL(val) = MAX_UNIQUE_RESULT_ROWS * 100;
-          }else if(pSchema->bytes < 100){
-            GET_INT64_VAL(val) = MAX_UNIQUE_RESULT_ROWS * 10;
-          }else{
-            GET_INT64_VAL(val) = MAX_UNIQUE_RESULT_ROWS;
-          }
+          GET_INT64_VAL(val) = MAX_UNIQUE_RESULT_ROWS;
         }
 
         int64_t numRowsSelected = GET_INT64_VAL(val);
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index 099f01e9a708377b076895d3d472d653b977fc56..47efc29031b972818fbc540150613b61c0b199c5 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -1528,6 +1528,11 @@ void handleDownstreamOperator(SSqlObj** pSqlObjList, int32_t numOfUpstream, SQue
 
     tscDebug("0x%"PRIx64" create QInfo 0x%"PRIx64" to execute the main query while all nest queries are ready", pSql->self, pSql->self);
     px->pQInfo = createQInfoFromQueryNode(px, &tableGroupInfo, pSourceOperator, NULL, NULL, MASTER_SCAN, pSql->self);
+    if (px->pQInfo == NULL) {
+      tscAsyncResultOnError(pSql);
+      pOutput->code = TSDB_CODE_QRY_OUT_OF_MEMORY;
+      return;
+    }
 
     px->pQInfo->runtimeEnv.udfIsCopy = true;
     px->pQInfo->runtimeEnv.pUdfInfo = pUdfInfo;
diff --git a/src/query/inc/qResultbuf.h b/src/query/inc/qResultbuf.h
index 5191ddab46411032e25f4663122b04931281b132..7c33f729acca052b6123b5139c235195231bb9f2 100644
--- a/src/query/inc/qResultbuf.h
+++ b/src/query/inc/qResultbuf.h
@@ -79,9 +79,9 @@ typedef struct SDiskbasedResultBuf {
 #define DEFAULT_INTERN_BUF_PAGE_SIZE  (1024L)                          // in bytes
 #define PAGE_INFO_INITIALIZER         (SPageDiskInfo){-1, -1}
 #define MAX_UNIQUE_RESULT_ROWS (10000)
-#define MAX_UNIQUE_RESULT_SIZE (1024*1024*10)
-#define MAX_MODE_INNER_RESULT_ROWS (1000000)
-#define MAX_MODE_INNER_RESULT_SIZE (1024*1024*10)
+#define MAX_UNIQUE_RESULT_SIZE (1024*1024)
+#define MAX_MODE_INNER_RESULT_ROWS (10000)
+#define MAX_MODE_INNER_RESULT_SIZE (1024*1024)
 /**
  * create disk-based result buffer
  * @param pResultBuf
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 5e035463f835102ff444466fdcc65e5e02b5425a..1facab0b34e271394c37486ee2b900ec89c8f71c 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -330,11 +330,11 @@ SSDataBlock* createOutputBuf(SExprInfo* pExpr, int32_t numOfOutput, int32_t numO
 
     int64_t tmp = idata.info.bytes;
     tmp *= numOfRows;
-    if (tmp >= 1024*1024*1024) {   // 1G
-      qError("size is too large, failed to allocate column buffer for output buffer");
+    if (tmp >= INT32_MAX) {
+      qError("size is too large, failed to allocate column buffer for output buffer:%" PRId64, tmp);
       tmp = 128*1024*1024;
     }
-    int32_t size = (int32_t)MAX(tmp, minSize);
+    size_t size = (size_t)MAX(tmp, minSize);
     idata.pData = calloc(1, size);  // at least to hold a pointer on x64 platform
     if (idata.pData == NULL) {
       qError("failed to allocate column buffer for output buffer");
@@ -2131,7 +2131,7 @@ static int32_t setupQueryRuntimeEnv(SQueryRuntimeEnv *pRuntimeEnv, int32_t numOf
   pRuntimeEnv->sasArray = calloc(pQueryAttr->numOfOutput, sizeof(SScalarExprSupport));
 
   if (pRuntimeEnv->sasArray == NULL || pRuntimeEnv->pResultRowHashTable == NULL || pRuntimeEnv->keyBuf == NULL ||
-      pRuntimeEnv->prevRow == NULL  || pRuntimeEnv->tagVal == NULL) {
+      pRuntimeEnv->prevRow == NULL  || pRuntimeEnv->tagVal == NULL || pRuntimeEnv->pool == NULL) {
     goto _clean;
   }
 
diff --git a/src/query/src/qUtil.c b/src/query/src/qUtil.c
index 67dfc130ed58d416500d278c60945114ef8a3fe4..1628c2d5111268111ca88cbe511095e8334453ed 100644
--- a/src/query/src/qUtil.c
+++ b/src/query/src/qUtil.c
@@ -204,9 +204,9 @@ SResultRowPool* initResultRowPool(size_t size) {
   p->elemSize = (int32_t) size;
   int64_t tmp = p->elemSize;
   tmp *= p->numOfElemPerBlock;
-  if (tmp > 1024*1024*1024){
+  if (tmp > INT32_MAX){
     qError("ResultRow blockSize is too large:%" PRId64, tmp);
-    tmp = 128*1024*1024;
+    return NULL;
   }
   p->blockSize = (int32_t)tmp;
   p->position.pos = 0;
@@ -223,6 +223,7 @@ SResultRow* getNewResultRow(SResultRowPool* p) {
   void* ptr = NULL;
   if (p->position.pos == 0) {
     ptr = calloc(1, p->blockSize);
+    if(ptr == NULL) return NULL;
     taosArrayPush(p->pData, &ptr);
 
   } else {