--- sql-common/net_serv.cc	2021-12-18 00:07:27.000000000 +0800
+++ /root/mysql-8.0.28/sql-common/net_serv.cc	2022-02-28 11:56:42.867813079 +0800
@@ -2232,6 +2232,7 @@ ulong my_net_read(NET *net) {
 void my_net_set_read_timeout(NET *net, uint timeout) {
   DBUG_TRACE;
   DBUG_PRINT("enter", ("timeout: %d", timeout));
+  if (net->read_timeout == timeout) return;
   net->read_timeout = timeout;
   if (net->vio) vio_timeout(net->vio, 0, timeout);
 }
@@ -2239,6 +2240,7 @@ void my_net_set_read_timeout(NET *net, u
 void my_net_set_write_timeout(NET *net, uint timeout) {
   DBUG_TRACE;
   DBUG_PRINT("enter", ("timeout: %d", timeout));
+  if (net->write_timeout == timeout) return;
   net->write_timeout = timeout;
   if (net->vio) vio_timeout(net->vio, 1, timeout);
 }