mysql瑣碎操作雜記

1、索引相關

檢視表索引

show index from `user`

檢視sql的執行計畫

explain select * from where user

2、儲存過程相關

檢視儲存過程

show

procedure

status

檢視儲存過程aaa的ddl

show create procedure aaa

呼叫儲存過程

call aaa()

3、檢視資料庫的連線情況

show processlist;

4、檢視資料庫大小

mysql [information_schema]> select concat(round(sum(data_length/1024/1024), 2),'mb') as data from tables where table_schema='db_a';

mysql [information_schema]> select concat(round(sum(data_length/1024/1024), 2),'mb') as data from tables where table_schema='db_b';

mysql [information_schema]> select concat(round(sum(data_length/1024/1024),2),'mb') as data from tables;

select concat(round(sum(data_length/1024/1024),2),'m') from tables where table_schema=』資料庫名』 and table_name=』表名』;

select sum(data_length)+sum(index_length) from information_schema.tables where table_schema='資料庫名';

5、show engine innodb status 檢視引擎日誌，包含如下面內容，常用的比如檢視死鎖日誌

background thread

semaphores

latest detected deadlock

transactions

file i/o

insert buffer and adaptive hash index

logbuffer pool and memory

individual buffer pool info

row operations

6、information_schema中的三張表:innodb_trx、innodb_locks、innodb_lock_waits，通過這三張表，可以更簡單地監控當前的事務並分析可能存在的鎖等待問題。

比如直接查sql select * from innodb_trx，排查分析鎖等待的問題，可以查出有問題的事務，然後處理它，比如kill掉等操作