diff --git a/inc/toolsdef.h b/inc/toolsdef.h
index aaf918b8..f2a5104b 100644
--- a/inc/toolsdef.h
+++ b/inc/toolsdef.h
@@ -223,6 +223,7 @@ int32_t       toolsCloseDir(TdDirPtr *ppDir);
 
 int64_t atomic_add_fetch_64(int64_t volatile* ptr, int64_t val);
 int32_t toolsGetNumberOfCores();
+int32_t toolsGetPhysicalMemory();
 
 int64_t toolsGetTimestamp(int32_t precision);
 void    toolsMsleep(int32_t mseconds);
diff --git a/src/benchInsert.c b/src/benchInsert.c
index 4a3d3be1..106fedb7 100644
--- a/src/benchInsert.c
+++ b/src/benchInsert.c
@@ -493,6 +493,34 @@ int32_t getVgroupsOfDb(SBenchConn *conn, SDataBase *database) {
 }
 #endif  // TD_VER_COMPATIBLE_3_0_0_0
 
+// export from taos osSysinfo.c
+int32_t taosGetTotalMemory(int64_t *totalKB); 
+
+int32_t toolsGetDefaultVGroups() {
+    int32_t cores = toolsGetNumberOfCores();
+    if (cores < 3 ) {
+        return 1;
+    }
+
+    int64_t MemKB = 0;
+    taosGetTotalMemory(&MemKB);
+
+    infoPrint("check local machine CPU: %d Memory:%d MB \n", cores, (int32_t)(MemKB/1024));
+    if (MemKB <= 2*1024*1024) { // 2G
+        return 1;
+    } else if (MemKB <= 4*1024*1024) { // 4G
+        return 2;
+    } else if (MemKB <= 8*1024*1024) { // 8G
+        return 3;
+    } else if (MemKB <= 16*1024*1024) { // 16G
+        return 4;
+    } else if (MemKB <= 32*1024*1024) { // 32G
+        return 5;
+    } else {
+        return cores / 2;
+    }
+}
+
 int geneDbCreateCmd(SDataBase *database, char *command, int remainVnodes) {
     int dataLen = 0;
     int n;
@@ -505,7 +533,7 @@ int geneDbCreateCmd(SDataBase *database, char *command, int remainVnodes) {
                             database->dbName,
                             (-1 != g_arguments->inputted_vgroups)?
                             g_arguments->inputted_vgroups:
-                            min(remainVnodes, toolsGetNumberOfCores()));
+                            min(remainVnodes, toolsGetDefaultVGroups()));
     } else {
         n = snprintf(command + dataLen, SHORT_1K_SQL_BUFF_LEN - dataLen,
                     g_arguments->escape_character