diff --git a/src/common/inc/tglobal.h b/src/common/inc/tglobal.h
index 284e71801603e8184f14e96bb42b4d1896060780..9b498e8bd2ab9e8bf2f31f5a91e6d881544a34f9 100644
--- a/src/common/inc/tglobal.h
+++ b/src/common/inc/tglobal.h
@@ -57,7 +57,8 @@ extern int32_t  tsCompressMsgSize;
 extern char     tsTempDir[];
 
 //query buffer management
-extern int32_t  tsQueryBufferSize;      // maximum allowed usage buffer for each data node during query processing
+extern int32_t  tsQueryBufferSize;      // maximum allowed usage buffer size in MB for each data node during query processing
+extern int64_t  tsQueryBufferSizeBytes; // maximum allowed usage buffer size in byte for each data node during query processing
 extern int32_t  tsRetrieveBlockingModel;// retrieve threads will be blocked
 
 extern int8_t   tsKeepOriginalColumnName;
diff --git a/src/common/src/tglobal.c b/src/common/src/tglobal.c
index 4a9b4c3e4357679e034fbda8ae296ed7b3589483..43b63de935caf5172b4d5e91f4648a458bc653ec 100644
--- a/src/common/src/tglobal.c
+++ b/src/common/src/tglobal.c
@@ -105,6 +105,7 @@ int64_t tsMaxRetentWindow = 24 * 3600L;  // maximum time window tolerance
 // 0  no query allowed, queries are disabled
 // positive value (in MB)
 int32_t tsQueryBufferSize = -1;
+int64_t tsQueryBufferSizeBytes = -1;
 
 // in retrieve blocking model, the retrieve threads will wait for the completion of the query processing.
 int32_t tsRetrieveBlockingModel = 0;
@@ -283,7 +284,7 @@ bool taosCfgDynamicOptions(char *msg) {
     int32_t cfgLen = (int32_t)strlen(cfg->option);
     if (cfgLen != olen) continue;
     if (strncasecmp(option, cfg->option, olen) != 0) continue;
-    if (cfg->valType != TAOS_CFG_VTYPE_INT32) {
+    if (cfg->valType == TAOS_CFG_VTYPE_INT32) {
       *((int32_t *)cfg->ptr) = vint;
     } else {
       *((int8_t *)cfg->ptr) = (int8_t)vint;
@@ -1488,6 +1489,10 @@ int32_t taosCheckGlobalCfg() {
   tsSyncPort = tsServerPort + TSDB_PORT_SYNC;
   tsHttpPort = tsServerPort + TSDB_PORT_HTTP;
 
+  if (tsQueryBufferSize >= 0) {
+    tsQueryBufferSizeBytes = tsQueryBufferSize * 1048576;
+  }
+
   taosPrintGlobalCfg();
 
   return 0;
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 6e1945407cc0e7682a884a99ea0095bdc27c7b2c..f13e9ef62359d66993f50d21f986fba19fc80e3a 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -7730,15 +7730,15 @@ static int64_t getQuerySupportBufSize(size_t numOfTables) {
 
 int32_t checkForQueryBuf(size_t numOfTables) {
   int64_t t = getQuerySupportBufSize(numOfTables);
-  if (tsQueryBufferSize < 0) {
+  if (tsQueryBufferSizeBytes < 0) {
     return TSDB_CODE_SUCCESS;
-  } else if (tsQueryBufferSize > 0) {
+  } else if (tsQueryBufferSizeBytes > 0) {
 
     while(1) {
-      int64_t s = tsQueryBufferSize;
+      int64_t s = tsQueryBufferSizeBytes;
       int64_t remain = s - t;
       if (remain >= 0) {
-        if (atomic_val_compare_exchange_64(&tsQueryBufferSize, s, remain) == s) {
+        if (atomic_val_compare_exchange_64(&tsQueryBufferSizeBytes, s, remain) == s) {
           return TSDB_CODE_SUCCESS;
         }
       } else {
@@ -7752,14 +7752,14 @@ int32_t checkForQueryBuf(size_t numOfTables) {
 }
 
 void releaseQueryBuf(size_t numOfTables) {
-  if (tsQueryBufferSize <= 0) {
+  if (tsQueryBufferSizeBytes < 0) {
     return;
   }
 
   int64_t t = getQuerySupportBufSize(numOfTables);
 
   // restore value is not enough buffer available
-  atomic_add_fetch_64(&tsQueryBufferSize, t);
+  atomic_add_fetch_64(&tsQueryBufferSizeBytes, t);
 }
 
 void* qGetResultRetrieveMsg(qinfo_t qinfo) {
@@ -7915,3 +7915,4 @@ void** qReleaseQInfo(void* pMgmt, void* pQInfo, bool freeHandle) {
   taosCacheRelease(pQueryMgmt->qinfoPool, pQInfo, freeHandle);
   return 0;
 }
+   
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