strace结果：
strace -e select -p 18170

strace: Process 18170 attached
select(7, [6], [], [], NULL

ls -alh /proc/18170/fd 结果

dr-x------ 2 root root  0 Feb  9 12:00 .
dr-xr-xr-x 9 root root  0 Jan 22 18:42 ..
lr-x------ 1 root root 64 Feb  9 12:00 0 -> /dev/null
l-wx------ 1 root root 64 Feb  9 12:00 1 -> /data0/log-data/php_mq.log
lrwx------ 1 root root 64 Feb  9 12:00 10 -> /etc/pki/nssdb/key4.db
l-wx------ 1 root root 64 Feb  9 12:00 2 -> /data0/log-data/php_mq.log
lrwx------ 1 root root 64 Feb  9 12:00 3 -> /tmp/.ZendSem.7V5AyU (deleted)
l-wx------ 1 root root 64 Feb  9 12:00 4 -> /data0/log-data/php_mq.log
l-wx------ 1 root root 64 Feb  9 12:00 5 -> /data0/log-data/php_mq.log
lrwx------ 1 root root 64 Feb  9 12:00 6 -> socket:[308698175]
lrwx------ 1 root root 64 Feb  9 12:00 7 -> socket:[308698332]
lrwx------ 1 root root 64 Feb  9 12:00 9 -> /etc/pki/nssdb/cert9.db

inode 308698332 信息
cat /proc/net/tcp | grep 308698332

410: 本地ip:8F88 远端ip:0CEA 01 00000000:00000000 02:00000631 00000000     0        0 308698332 2 ffff970f70bbae80 20 4 1 10 9

mysql超时配置

Variable_name	Value
connect_timeout	10
delayed_insert_timeout	300
have_statement_timeout	YES
innodb_flush_log_at_timeout	1
innodb_lock_wait_timeout	50
innodb_rollback_on_timeout	OFF
interactive_timeout	7200
lock_wait_timeout	31536000
net_read_timeout	30
net_write_timeout	600
rds_trx_changes_idle_timeout	0
rds_trx_idle_timeout	0
rds_trx_readonly_idle_timeout	0
rpl_semi_sync_master_timeout	1000
rpl_stop_slave_timeout	31536000
slave_net_timeout	60
thread_pool_idle_timeout	10
wait_timeout	86400