mysql 基础-搭建的两台从库server-id相同，会出现什么情况？搭建的主库和从库server-id相同，又会出现什么情况？

主从相同时 ，出现从库不能io线程不能同步，show slave status:

Fatal error: The slave I/O thread stops because master and slavehave equal MySQL server ids; these ids must be different for replication to work(or the --replicate-same-server-id option must be used on slave but this doesnot always make sense; please check
the manual before using it).

正如上面所说，可以配置--replicate-same-server-id,但是如果配置这个选项就不能配置--slave-log-updates,因为这样可能会导致内循环，如下：

using --replicate-same-server-id in conjunction with--log-slave-updates is impossible, it would lead to infinite loops in thisserver.

从和从相同：

从服务器的io线程总是在这个之间切换，两个从库的io线程轮流争抢主库连接。

Queueing master event to the relay log和 Waiting toreconnect after a failed master event read。

错误日志中循环出现

120810 16:12:53 [Note] Slave: received end packet from server,apparent master shutdown:

120810 16:12:53 [Note] Slave I/O thread: Failed reading log event,reconnecting to retry, log 'mysql-bin.000023' at postion 537

[c1]直接说：主从相同时从库同步会停止，然后再列出错误日志，否则回答的没有重点

[c2]哪个？直接回答：两个从库的io线程会争抢id，交互断开，注意提炼