mysql性能监控

参考:http://blog.csdn.net/ylqmf/article/details/6834897

查看mysql数据库的状态

show status;

刷新状态

flush status;

查看活动连接内容
SHOW PROCESSLIST;

查看当前连接数 SHOW STATUS LIKE 'Threads_%';
Threads_cached:被缓存的线程的个数
Threads_running：处于激活状态的线程的个数
Threads_connected：当前连接的线程的个数
Threads_created：总共被创建的线程的个数

线程缓存命中率TCH（Thread cache hits）

Thread_connected = SHOW GLOBAL STATUS LIKE 'Threads_created';
Connections = SHOW GLOBAL STATUS LIKE 'Connections';
TCH=(1 - (Threads_created / Connections)) * 100
如果 TCH数小于90%,创建连接耗费了时间,增大Thread_cached数量

每秒查询率QPS（Query Per Seconds）
Questions = SHOW GLOBAL STATUS LIKE 'Questions';
Uptime = SHOW GLOBAL STATUS LIKE 'Uptime';

QPS=Questions/Uptime 

系统吞吐量TPS
Com_commit = SHOW GLOBAL STATUS LIKE 'Com_commit';
Com_rollback = SHOW GLOBAL STATUS LIKE 'Com_rollback';
Uptime = SHOW GLOBAL STATUS LIKE 'Uptime';

TPS=(Com_commit + Com_rollback)/Uptime

读写率Read/Writes Ratio
Qcache_hits = SHOW GLOBAL STATUS LIKE 'Qcache_hits';
Com_select = SHOW GLOBAL STATUS LIKE 'Com_select';
Com_insert = SHOW GLOBAL STATUS LIKE 'Com_insert';
Com_update = SHOW GLOBAL STATUS LIKE 'Com_update';
Com_delete = SHOW GLOBAL STATUS LIKE 'Com_delete';
Com_replace = SHOW GLOBAL STATUS LIKE 'Com_replace';

R/W=(Com_select + Qcache_hits) / (Com_insert + Com_update + Com_delete + Com_replace) * 100

每分钟的慢查询SQPM(Slow queries per minute)
Slow_queries = SHOW GLOBAL STATUS LIKE 'Slow_queries';
Uptime = SHOW GLOBAL STATUS LIKE 'Uptime';
SQPM=Slow_queries / (Uptime/60)

Slow queries /Questions Ratio
Slow_queries = SHOW GLOBAL STATUS LIKE 'Slow_queries';
Questions = SHOW GLOBAL STATUS LIKE 'Questions';
S/Q=Slow_queries/Questions 

Full_join per minute
Select_full_join = SHOW GLOBAL STATUS LIKE 'Select_full_join';
Uptime = SHOW GLOBAL STATUS LIKE 'Uptime';
FJPM=Select_full_join / (Uptime/60)
没有使用索引而造成的full_join,优化索引去吧

Innodb buffer read hits
Innodb_buffer_pool_reads = SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_reads';
Innodb_buffer_pool_read_requests = SHOW GLOBAL STATUS LIKE 'Innodb_buffer_pool_read_requests';
IFRH=(1 - Innodb_buffer_pool_reads/Innodb_buffer_pool_read_requests) * 100
InnoDB Buffer命中率 目标 95%-99%;

Table Cache
Open_tables= SHOW GLOBAL STATUS LIKE 'Open_tables';
Opened_tables= SHOW GLOBAL STATUS LIKE 'Opened_tables';
table_cache= SHOW GLOBAL STATUS LIKE 'table_cache';
table_cache应该大于 Open_tables 小于 Opened_tables 

Temp tables to Disk ratio

Created_tmp_tables = show global status like 'Created_tmp_tables';
Created_tmp_disk_tables = show global status like 'Created_tmp_disk_tables';

TDR=(Created_tmp_disk_tables/Created_tmp_tables)*100

SHOW GLOBAL STATUS LIKE 'Innodb_row_lock_%';

• Innodb_row_lock_current_waits

  The number of row locks currently being waited for.

• Innodb_row_lock_time

  The total time spent in acquiring row locks, in milliseconds.

• Innodb_row_lock_time_avg

  The average time to acquire a row lock, in milliseconds.

• Innodb_row_lock_time_max

  The maximum time to acquire a row lock, in milliseconds. 

• Innodb_row_lock_waits

  The number of times a row lock had to be waited for.