# 11 监控与优化 ## 11.1 监控指标  ### 11.1.1 QPS ```mysql mysql> show global status like 'Com%'; mysql> show global status like 'Queries'; +---------------+---------+ | Variable_name | Value | +---------------+---------+ | Queries | 1983766 | +---------------+---------+ 1 row in set (0.00 sec) ``` QPS = ( Queries 2- Queries 1 ) / 间隔时间 ```mysql mysql> show global status where variable_name in ('Queries','uptime'); +---------------+---------+ | Variable_name | Value | +---------------+---------+ | Queries | 1983768 | | Uptime | 1364443 | +---------------+---------+ 2 rows in set (0.00 sec) ``` ### 11.1.2 TPS ```mysql mysql> show global status where variable_name in ('com_insert','com_update','com_delete','uptime'); +---------------+---------+ | Variable_name | Value | +---------------+---------+ | Com_delete | 23676 | | Com_insert | 793072 | | Com_update | 259586 | | Uptime | 1364651 | +---------------+---------+ 4 rows in set (0.00 sec) ``` Transaction_sum= Com_delete+ Com_insert+ Com_update TPS = (Transaction_sum 2 - Transaction_sum 1 ) / (time 2 - time 1) ### 11.1.3 并发数 ```mysql mysql> show global status like 'Threads_running'; +-----------------+-------+ | Variable_name | Value | +-----------------+-------+ | Threads_running | 2 | +-----------------+-------+ 1 row in set (0.01 sec) ``` ### 11.1.4 连接数 ```mysql # 最大连接数 mysql> show global status like 'max_used_connections%'; +---------------------------+---------------------+ | Variable_name | Value | +---------------------------+---------------------+ | Max_used_connections | 22 | | Max_used_connections_time | 2019-09-04 13:49:52 | +---------------------------+---------------------+ 2 rows in set (0.00 sec) # 当前连接数 mysql> show global status like 'threads_connected'; +-------------------+-------+ | Variable_name | Value | +-------------------+-------+ | Threads_connected | 2 | +-------------------+-------+ 1 row in set (0.01 sec) ``` ### 11.1.5 缓存命中率 ```mysql ##从缓存中读取的次数 mysql> show global status like 'innodb_buffer_pool_read_requests'; +----------------------------------+----------+ | Variable_name | Value | +----------------------------------+----------+ | Innodb_buffer_pool_read_requests | 16217299 | +----------------------------------+----------+ 1 row in set (0.00 sec) ##从物理磁盘读取的次数 mysql> show global status like 'innodb_buffer_pool_reads'; +--------------------------+-------+ | Variable_name | Value | +--------------------------+-------+ | Innodb_buffer_pool_reads | 2067 | +--------------------------+-------+ 1 row in set (0.00 sec) ``` 缓存命中率 = ( innodb_buffer_pool_read_requests - innodb_buffer_pool_reads ) / innodb_buffer_pool_reads * 100% ### 11.1.6 服务可用性 1. 周期连接，执行查询：select @@version; 或 select user(); 2. mysqladmin -uroot -pxxx -hxxxx ping ### 11.1.7 阻塞 ```mysql ##< mysql 5.7 SELECT b.trx_mysql_thread_id as '被阻塞的线程', b.trx_query as '被阻塞的SQL', c.trx_mysql_thread_id as '阻塞线程', c.trx_query as '阻塞SQL', UNIX_TIMESTAMP()-UNIX_TIMESTAMP(c.trx_started)) as '阻塞时间' FROM information_schema.INNODB_LOCK_WAITS a JOIN information_schema.INNODB_TRX b ON a.requesting_trx_id=b.trx_id JOIN information_schema.INNODB_TRX c ON a.blocking_trx_id=c.trx_id WHERE (UNIX_TIMESTAMP()-UNIX_TIMESTAMP(c.trx_started))>30 ##> mysql 5.7 SELECT waiting_pid AS '被阻塞的线程', waiting_query AS '被阻塞的SQL', blocking_pid AS '阻塞线程', blocking_query AS '阻塞SQL', wait_age AS '阻塞时间', sql_kill_blocking_query AS '建议操作' FROM sys.innodb_lock_waits WHERE (UNIX_TIMESTAMP()-UNIX_TIMESTAMP(wait_started))>30 ``` ### 11.1.8 死锁 ```shell ##pt工具 pt-deadlock-logger u=admin, p=123456, h=127.0.0.1 \ --create-dest-table \ --dest u=admin,p=123456, h=127.0.0.1.D=dba,t=deadlock ##全局参数，日志监控 mysql> set persist innodb_print_all_deadlocks=on; ``` ### 11.1.9 慢查询 1. 监控慢查询日志 2. 通过information_shcema.processlist表实时监控 ### 11.1.10 主从延迟 1. show slave status\G 2. pt-heartbeat ```shell ##主库 pt-heartbeat --user=xx --password=xxx -h master --create-table --database xxx --update --daemonize --interval=1 ##从库 pt-hearbeat --user=xx --password=xx -h slave --database xxx --monitor --daemonize --log /tmp/slave_lag.log ``` ### 11.1.11 主从状态 1. show slave status\G IO/SQL 两个线程状态（yes or no) ## 11.2 负载问题  ## 11.3 优化