change maxVgroupsPerDb to 16

src/inc/taosdef.h

@@ -294,6 +294,8 @@ void tsDataSwap(void *pLeft, void *pRight, int32_t type, int32_t size, void* buf
 #define TSDB_CQ_SQL_SIZE          1024
 #define TSDB_MIN_VNODES           64
 #define TSDB_MAX_VNODES           2048
+#define TSDB_MIN_VNODES_PER_DB    2
+#define TSDB_MAX_VNODES_PER_DB    16
 
 #define TSDB_DNODE_ROLE_ANY       0
 #define TSDB_DNODE_ROLE_MGMT      1

src/mnode/src/mnodeVgroup.c

@@ -434,7 +434,8 @@ int32_t mnodeGetAvailableVgroup(SMnodeMsg *pMsg, SVgObj **ppVgroup, int32_t *pSi
   int maxVgroupsPerDb = tsMaxVgroupsPerDb;
   if (maxVgroupsPerDb <= 0) {
     maxVgroupsPerDb = mnodeGetOnlinDnodesCpuCoreNum();
-    maxVgroupsPerDb = MAX(maxVgroupsPerDb, 2);
+    maxVgroupsPerDb = MAX(maxVgroupsPerDb, TSDB_MIN_VNODES_PER_DB);
+    maxVgroupsPerDb = MIN(maxVgroupsPerDb, TSDB_MAX_VNODES_PER_DB);
   }
 
   int32_t code = TSDB_CODE_MND_NO_ENOUGH_DNODES;