show slave hosts; mysql> show slave hosts; +------------+---------------+------+------------+--------------------------------------+ | Server_id | Host | Port | Master_id | Slave_UUID | +------------+---------------+------+------------+--------------------------------------+ | 1647312172 | 192.168.11.14 | 3306 | 1647312173 | af5b1a5b-a409-11ec-b404-0050568a5583 | +------------+---------------+------+------------+--------------------------------------+ 1 row in set (0.00 sec)
主库上通过 show slave hosts 可以很直观的显示从库信息，当然包含ip了。
在从库上执行 show slave hosts 是没有结果的。
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mysql> show slave hosts; Empty set (0.00 sec)
如果不知道当前主机是主库还是从库，可以通过 show slave hosts 来判断，如果有信息说明当前是主库，同时也会显示从库的信息。如果没有信息，然后通过show slave status\G 进一步确认从库信息，同时也可以 Master_Host 看到主库的ip信息。
show process list
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mysql> show processlist; +--------+-----------------+---------------------+------+------------------+--------+---------------------------------------------------------------+------------------+ | Id | User | Host | db | Command | Time | State | Info | +--------+-----------------+---------------------+------+------------------+--------+---------------------------------------------------------------+------------------+ | 1 | event_scheduler | localhost | NULL | Daemon | 405282 | Waiting on empty queue | NULL | | 7520 | repl | 192.168.11.14:46544 | NULL | Binlog Dump GTID | 421846 | Master has sent all binlog to slave; waiting for more updates | NULL | | 330853 | root | 127.0.0.1:35564 | NULL | Query | 0 | starting | show processlist | | 330857 | _ha | 192.168.11.4:60294 | NULL | Sleep | 5 | | NULL | | 330858 | _ha | 192.168.11.4:60298 | NULL | Sleep | 5 | | NULL | | 330859 | _ha | 192.168.11.4:60300 | NULL | Sleep | 5 | | NULL | +--------+-----------------+---------------------+------+------------------+--------+---------------------------------------------------------------+------------------+ 6 rows in set (0.00 sec)
通过在主库上执行 show processlist，可以看到 state 对应的 Master has sent all binlog to slave; waiting for more updates 的 host 就是从库的ip信息。
如果是在从库上执行 show processlist，会有 Slave has read all relay log; waiting for more updates 的进程信息，通过 show slave status\G 显示的 Master_Host: 192.168.11.15 可以确定主库的 IP 信息。
show processlist; 数据来自于 information_schema.processlist ，可以通过如下SQL 查看。
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select substring_index(host, ':', 1) as Host from information_schema.processlist where command IN ('Binlog Dump', 'Binlog Dump GTID');
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mysql> select substring_index(host, ‘:’, 1) as Host from information_schema.processlist where -> command IN (‘Binlog Dump’, ‘Binlog Dump GTID’); +—————+ | Host | +—————+ | 192.168.11.14 | +—————+ 1 row in set (0.00 sec)