I often find SQL errors on the client side:
[ERRO] {a8f089871e3014188d84ed5711f746f0} [10093 ms] [xx] [xxxx] [rows:0 ] SELECT `status`,`tag_sync`,`resource_id` FROM `xxxx` WHERE `src_instance_id`='xxxx' LIMIT 1
Error: invalid connection
[ERRO] {8573ecb437cb0c1890ae452ac285ca35} [15737 ms] [xx] [xxx] [rows:0 ] SELECT `status`,`tag_sync`,`resource_id` FROM `xxx` WHERE `src_instance_id`='xxxx' LIMIT 1
Error: invalid connection
[ERRO] {52c80cb863970f184fb0921557bced90} [ 92 ms] [xxx] [xxxx] [rows:0 ] SELECT `status`,`tag_sync`,`resource_id` FROM `xx` WHERE `src_instance_id`='xxxx' LIMIT 1
Error: invalid connection
You can see that two error SQL statements were executed for 10 seconds、15 seconds and 92ms respectively, And there is no slow SQL.
I can confirm:
- two SQL statements are indexed and there is very little data in the table.
- mysql server is not overload at the same time.
Here are my parameters：
show global variables like "%timeout%"
cdb_kill_idle_trans_timeout 0
connect_timeout 10
delayed_insert_timeout 300
have_statement_timeout YES
innodb_flush_log_at_timeout 1
innodb_hot_update_wait_timeout 1000000
innodb_lock_wait_timeout 50
innodb_rollback_on_timeout OFF
interactive_timeout 7200
lock_wait_timeout 31536000
net_read_timeout 30
net_write_timeout 60
rpl_semi_sync_master_timeout 10000
rpl_stop_slave_timeout 120
slave_net_timeout 120
thread_pool_idle_timeout 60
wait_timeout 3600
version: 5.7.36