repmgr确实可以实现这种功能。这是通过配置复制延迟检查来实现的。以下是具体的实现方法：复制延迟检查：repmgr提供了一个名为replication_lag_critical的参数。当备库的复制延迟超过这个阈值时，repmgr会认为该备库不适合进行故障转移。配置方法：repmgr确实可以实现基于复制延迟控制自动故障转移。这是通过配置复制延迟检查来实现的。实现方法1. 复制延迟检查repmgr提

找不到，binlog中不包括会话信息。

排查过时区问题么

explain 看看

Question: 28The MySQL error log shows:InnoDB: Warning: a long semaphore wait:The relevant parts of t

Question: 26What two statements are true regarding FLUSH TABLES FOR EXPORT? A. It can be used to ex

Using index condition 是索引下推Using index 才是覆盖索引

1、假设使用idx_memid索引获取数据，需要遍历idx_memid，再根据主键id回表查询；最终需要扫描两个索引树。2、根据主键访问只需扫描一次全表后，内存排序。1比2需要的io次数多一倍，io和memory的cost至少相差一个量级。肯定选2执行了。

Question: 22Which three are key advantages of standard MySQL replication? A. supports native automa

Id与thead_id相同，都是对应客户端连接的connection id。performance_schema.threads中包含了mysql内部的所有线程，包括前台线程和后台线程。慢查询输出后台线程id没有意义。

可以。innodb引擎的表执行optimize时，实际就是执行ALTER TABLE xxx FORCE来重建表从而更新统计数据和清理碎片。可以使用pt-osc或gh-ost执行ALTER TABLE xxx ENGINE=innodb来重建表，避免阻塞业务。注意：使用pt-osc、gh-ost执行ddl语句时，会新建一个影子表后进行数据复制，影子表大小是<=原表的；因此需要至少预留大于目标表的磁

Question: 21Consider that local disk files are accessible via MySQL with commands such as: mysql> LO

还没人回答吗？

bcd正确

A single InnoDB table has been dropped by accident. You are unable to use an additional intermediat

You have installed MySQL Server for the first time on your system. However, the data directory alon

Host slave1 has ip address 192.0.2.10. Host slave2 has ip address 203.0.113.50 Examine these command

你不会以为mysql和pg是单线程的吧？

Question: 10You have just executed a manual backup by using this command: mysqlbackup -u root -p --

binlog2sql_go介绍日常工作中经常遇到需要解析binlog的场景，如：- 通过binlog查找sql执行记录- 通过binlog回滚某条sql- 主从故障切换后通过binlog修复数据- 审

Question: 9Which two statements are true about InnoDB auto-increment locking? A. InnoDB never uses

Question: 8Which two options describe how MySQL Server allocates memory? A. Each connection may have

因为next-key lock锁定的范围是((4,4),(10,7)],不是【4，10）。验证很简单，你把age为1的id改为100，可以插入(1,4)。

Question: 7You are setting up a new installation of MySQL Server 5.7 (a GA release.) You have used a

Question: 6Which three allocate memory per thread in MySQL? A. query cache B. thread cache C. read b

跳过a:4事务SET GTID_NEXT='a:4; BEGIN; COMMIT; SET GTID_NEXT='AUTOMATIC';

只写redo log。redo log也叫innodb log，由innodb的log 线程负责；binlog是server层的日志，写binlog的日志叫binlog dump

MySQL5.7 OCP每日一题