diff --git a/packaging/docker/Dockerfile b/packaging/docker/Dockerfile
index 629f8f9fd6a4167db6f30d29646263710602693a..c0ca674555aa66d1c848b89f8af3f26cc2ee97b6 100644
--- a/packaging/docker/Dockerfile
+++ b/packaging/docker/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:18.04
+FROM ubuntu:20.04
 
 WORKDIR /root
 
diff --git a/src/common/inc/tglobal.h b/src/common/inc/tglobal.h
index 26475834d5aa91a87e6f8e14e86b211d5b68d6d2..2f4aa4c2b2ad0822fcf7a45987b812376fe5d9f0 100644
--- a/src/common/inc/tglobal.h
+++ b/src/common/inc/tglobal.h
@@ -44,6 +44,7 @@ extern int32_t  tsDnodeId;
 // common
 extern int      tsRpcTimer;
 extern int      tsRpcMaxTime;
+extern int      tsRpcForceTcp; // all commands go to tcp protocol if this is enabled
 extern int32_t  tsMaxConnections;
 extern int32_t  tsMaxShellConns;
 extern int32_t  tsShellActivityTimer;
diff --git a/src/common/src/tglobal.c b/src/common/src/tglobal.c
index 1524f15b7d5df38fe5f9e75d5dd88c4dd6553f0d..3a4a87f69d3a3c86807fb3206d5303e50343b276 100644
--- a/src/common/src/tglobal.c
+++ b/src/common/src/tglobal.c
@@ -48,6 +48,7 @@ int32_t  tsDnodeId = 0;
 // common
 int32_t tsRpcTimer       = 1000;
 int32_t tsRpcMaxTime     = 600;  // seconds;
+int32_t tsRpcForceTcp    = 0;  //disable this, means query, show command use udp protocol as default
 int32_t tsMaxShellConns  = 50000;
 int32_t tsMaxConnections = 5000;
 int32_t tsShellActivityTimer  = 3;  // second
@@ -625,6 +626,16 @@ static void doInitGlobalConfig(void) {
   cfg.unitType = TAOS_CFG_UTYPE_MS;
   taosInitConfigOption(cfg);
 
+  cfg.option = "rpcForceTcp";
+  cfg.ptr = &tsRpcForceTcp;
+  cfg.valType = TAOS_CFG_VTYPE_INT32;
+  cfg.cfgType = TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_CLIENT;
+  cfg.minValue = 0;
+  cfg.maxValue = 1;
+  cfg.ptrLength = 0;
+  cfg.unitType = TAOS_CFG_UTYPE_NONE;
+  taosInitConfigOption(cfg);
+
   cfg.option = "rpcMaxTime";
   cfg.ptr = &tsRpcMaxTime;
   cfg.valType = TAOS_CFG_VTYPE_INT32;
diff --git a/src/rpc/src/rpcMain.c b/src/rpc/src/rpcMain.c
index 2ec508f050ea7cf916f8b1c1e6ff37d18fb96523..08e7551a2e8fe72a24825362c17cf413509de9c3 100644
--- a/src/rpc/src/rpcMain.c
+++ b/src/rpc/src/rpcMain.c
@@ -399,7 +399,7 @@ void rpcSendRequest(void *shandle, const SRpcEpSet *pEpSet, SRpcMsg *pMsg, int64
   pContext->oldInUse = pEpSet->inUse;
 
   pContext->connType = RPC_CONN_UDPC; 
-  if (contLen > tsRpcMaxUdpSize) pContext->connType = RPC_CONN_TCPC;
+  if (contLen > tsRpcMaxUdpSize || tsRpcForceTcp ) pContext->connType = RPC_CONN_TCPC;
 
   // connection type is application specific. 
   // for TDengine, all the query, show commands shall have TCP connection
@@ -409,7 +409,7 @@ void rpcSendRequest(void *shandle, const SRpcEpSet *pEpSet, SRpcMsg *pMsg, int64
     || type == TSDB_MSG_TYPE_CM_TABLES_META || type == TSDB_MSG_TYPE_CM_TABLE_META
     || type == TSDB_MSG_TYPE_CM_SHOW || type == TSDB_MSG_TYPE_DM_STATUS)
     pContext->connType = RPC_CONN_TCPC;
-  
+
   pContext->rid = taosAddRef(tsRpcRefId, pContext);
   if (pRid) *pRid = pContext->rid;