[td-225] add tcp transfer threshold

src/inc/tglobalcfg.h

@@ -122,6 +122,8 @@ extern int tsBalancePolicy;
 extern int tsOfflineThreshold;
 extern int tsMgmtEqualVnodeNum;
 
+extern int tsTCPTransferThreshold;
+
 extern int tsEnableHttpModule;
 extern int tsEnableMonitorModule;
 extern int tsRestRowLimit;

src/rpc/src/tudp.c

@@ -756,7 +756,8 @@ int taosSendUdpData(uint32_t ip, uint16_t port, char *data, int dataLen, void *c
 
   if (pConn == NULL || pConn->signature != pConn) return -1;
 
-  if (dataLen >= RPC_MAX_UDP_SIZE) return taosSendPacketViaTcp(ip, port, data, dataLen, chandle);
+  assert(tsTCPTransferThreshold <= RPC_MAX_UDP_SIZE && tsTCPTransferThreshold > 0);
+  if (dataLen >= tsTCPTransferThreshold) return taosSendPacketViaTcp(ip, port, data, dataLen, chandle);
 
   if (pConn->hash == NULL) {
     struct sockaddr_in destAdd;

src/util/src/tglobalcfg.c

@@ -130,6 +130,8 @@ int tsBalancePolicy = 0;           // 1-use sys.montor
 int tsOfflineThreshold = 864000;   // seconds 10days
 int tsMgmtEqualVnodeNum = 4;
 
+int tsTCPTransferThreshold = 65480;  // RPC_MAX_UDP_SIZE
+
 int tsEnableHttpModule = 1;
 int tsEnableMonitorModule = 1;
 int tsRestRowLimit = 10240;
@@ -710,6 +712,10 @@ static void doInitGlobalConfig() {
                      TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_CLIENT,
                      0, 0, tListLen(tsCharset), TSDB_CFG_UTYPE_NONE);
 
+  tsInitConfigOption(cfg++, "tcptransferThreshold", &tsTCPTransferThreshold, TSDB_CFG_VTYPE_INT,
+                     TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_SHOW,
+                     500, 65480, 0, TSDB_CFG_UTYPE_BYTE);
+
   // connect configs
   tsInitConfigOption(cfg++, "maxShellConns", &tsMaxShellConns, TSDB_CFG_VTYPE_INT,
                      TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_SHOW,