refactor: adjust the minimum number of fetch threads to 4

source/common/src/tglobal.c

@@ -412,12 +412,8 @@ static int32_t taosAddServerCfg(SConfig *pCfg) {
   tsNumOfVnodeQueryThreads = TMAX(tsNumOfVnodeQueryThreads, 2);
   if (cfgAddInt32(pCfg, "numOfVnodeQueryThreads", tsNumOfVnodeQueryThreads, 1, 1024, 0) != 0) return -1;
 
-#if 0
   tsNumOfVnodeFetchThreads = tsNumOfCores / 4;
   tsNumOfVnodeFetchThreads = TMAX(tsNumOfVnodeFetchThreads, 4);
-#else
-  tsNumOfVnodeFetchThreads = 1;
-#endif
   if (cfgAddInt32(pCfg, "numOfVnodeFetchThreads", tsNumOfVnodeFetchThreads, 1, 1024, 0) != 0) return -1;
 
   tsNumOfVnodeWriteThreads = tsNumOfCores;