mysql監控指標

1.最大連接數監控

show VARIABLES like "max_connections";  //最大連接數

show global status like 'Threads_connected'; //當前連接數

show global status like 'Threads_running'; //正在處理的連接數

show global status like 'Thread%'; //查看進行情況

 

2.死鎖或者阻塞監控

innodb引擎查看死鎖語句
select b.trx_mysql_thread_id AS '被阻塞線程',
b.trx_query AS '被阻塞SQL',
c.trx_mysql_thread_id AS '阻塞線程',
(UNIX_TIMESTAMP()-UNIX_TIMESTAMP(c.trx_started)) AS '阻塞時間'
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))>60;

 

 3.慢查詢配置

-- 打開sql執行記錄功能
set global log_output='TABLE';                             -- 輸出到表
set global log=ON;                                                -- 打開所有命令執行記錄功能general_log, 所有語句: 成功和未成功的.
set global log_slow_queries=ON;                        -- 打開慢查詢sql記錄slow_log, 執行成功的: 慢查詢語句和未使用索引的語句
set global long_query_time=0.1;                          -- 慢查詢時間限制(秒)
set global log_queries_not_using_indexes=ON;  -- 記錄未使用索引的sql語句


-- 查詢sql執行記錄
select * from mysql.slow_log order by 1;           -- 執行成功的：慢查詢語句,和未使用索引的語句
select * from mysql.general_log order by 1;      -- 所有語句：  成功和未成功的.


-- 關閉sql執行記錄
set global log=OFF;
set global log_slow_queries=OFF;