MYSQL常用SQL汇总

1、查看当前应用连接,连接数突增排查

select user,SUBSTRING_INDEX(host,':',1) as ip , count(*) as count,db from information_schema.processlist where host not in ('localhost') and user not in ('replicater') group by ip order by count;

2、查看表所属及大概行数,一般加字段索引时做参考

select TABLE_SCHEMA,TABLE_NAME,TABLE_ROWS from information_schema.tables where TABLE_NAME='表名';

3、查看表碎片,是否需要整理表释放物理空间

select table_name,table_rows,concat(round(DATA_LENGTH/1024/1024, 2), 'MB') as size,DATA_FREE/1024/1024 AS data_free_MB from information_schema.TABLES where table_schema='库名' order by DATA_LENGTH desc;

4、当前有没有锁

select * from information_schema.innodb_locks;

5、当前锁堵塞情况

select * from information_schema.innodb_lock_waits;

6、当前锁等待详细信息

select it.trx_mysql_thread_id, il.lock_id, il.lock_table, il.lock_mode, il.lock_type, it.trx_state, pl.USER||'@'||pl.HOST as user_host, pl.db, pl.command, pl.info, it.trx_started, it.trx_wait_started, now()-trx_wait_started as wait_seconds, il.lock_index, it.trx_weight, it.trx_rows_locked, it.trx_rows_modified from information_schema.INNODB_TRX it,information_schema.innodb_locks il,information_schema.processlist pl where it.trx_id = il.lock_trx_id and it.trx_mysql_thread_id = pl.id\G

7、最近一次死锁、未提交事物、CHECKPIONT、BUFFER POOL等

show engine innodb status\G

8、过滤无用线程信息可用pager

pager grep -v Sleep;show processlist;

9、查看当前运行的详细SQL

SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST WHERE info is not null\G

10、查看某条sql各阶段执行时间,可开启profiling功能

set global profiling=on;

11、查看用户信息

select user,host,password from mysql.user group by user;

12、分表时批量生成sql语句

select concat("select IP as ",TABLE_NAME," from ",TABLE_SCHEMA,".",TABLE_NAME," group by id;") from information_schema.TABLES where TABLE_NAME like 'table_%';

(注意:PERFORMANCE_SCHEMA是在5.5开始新增一个数据库,MySQL5.5默认是关闭的,需要手动开启,5.6默认开启)

[mysqld]

performance_schema=ON

13、查看哪些sql执行最多

SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,SUM_ROWS_SENT,SUM_ROWS_EXAMINED,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !='information_schema' ORDER BY COUNT_STAR desc LIMIT 1;

14、哪个SQL平均响应时间最多

SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,AVG_TIMER_WAIT,SUM_ROWS_SENT,SUM_ROWS_EXAMINED,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !='information_schema' ORDER BY AVG_TIMER_WAIT desc LIMIT 1\G

15、哪个SQL扫描的行数最多(IO消耗)

SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,AVG_TIMER_WAIT,SUM_ROWS_SENT,SUM_ROWS_EXAMINED,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !='information_schema' ORDER BY SUM_ROWS_EXAMINED desc LIMIT 1\G

16、哪个SQL使用的临时表最多

SELECT SCHEMA_NAME,DIGEST_TEXT,SUM_CREATED_TMP_DISK_TABLES,SUM_CREATED_TMP_TABLES,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !='information_schema' ORDER BY SUM_CREATED_TMP_DISK_TABLES desc LIMIT 1\G

17、哪个SQL返回的结果集最多(net消耗)

SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,SUM_ROWS_SENT,SUM_ROWS_SENT,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !='information_schema' ORDER BY SUM_ROWS_SENT desc LIMIT 1\G

18、哪个SQL排序数最多(CPU消耗)

SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,SUM_ROWS_SENT,SUM_SORT_ROWS,FIRST_SEEN,LAST_SEEN FROM performance_schema.events_statements_summary_by_digest where SCHEMA_NAME is not null and SCHEMA_NAME !='information_schema' ORDER BY SUM_SORT_ROWS desc LIMIT 1\G

19、哪个表、文件逻辑IO最多(热数据)

SELECT FILE_NAME,EVENT_NAME,COUNT_READ,SUM_NUMBER_OF_BYTES_READ,COUNT_WRITE,SUM_NUMBER_OF_BYTES_WRITE FROM performance_schema.file_summary_by_instance ORDER BY SUM_NUMBER_OF_BYTES_READ+SUM_NUMBER_OF_BYTES_WRITE DESC LIMIT 2\G

20、哪个索引使用最多

SELECT OBJECT_NAME, INDEX_NAME, COUNT_FETCH, COUNT_INSERT, COUNT_UPDATE, COUNT_DELETE FROM performance_schema.table_io_waits_summary_by_index_usage ORDER BY SUM_TIMER_WAIT DESC limit 1;

21、哪个索引没有使用过

SELECT OBJECT_SCHEMA, OBJECT_NAME, INDEX_NAME FROM performance_schema.table_io_waits_summary_by_index_usage WHERE INDEX_NAME IS NOT NULL AND COUNT_STAR = 0 AND OBJECT_SCHEMA <> 'mysql' ORDER BY OBJECT_SCHEMA,OBJECT_NAME;

22、哪个等待事件消耗的时间最多

SELECT EVENT_NAME, COUNT_STAR, SUM_TIMER_WAIT, AVG_TIMER_WAIT FROM events_waits_summary_global_by_event_name WHERE event_name != 'idle' ORDER BY SUM_TIMER_WAIT DESC LIMIT 1;

23、通过performance_schema库得到数据库运行的统计信息,更好分析定位问题和完善监控信息

打开标准的innodb监控:

CREATE TABLE innodb_monitor (a INT) ENGINE=INNODB;

打开innodb的锁监控:

CREATE TABLE innodb_lock_monitor (a INT) ENGINE=INNODB;

打开innodb表空间监控:

CREATE TABLE innodb_tablespace_monitor (a INT) ENGINE=INNODB;

打开innodb表监控:

CREATE TABLE innodb_table_monitor (a INT) ENGINE=INNODB;

24、添加主键

alter table xxx add constraint primary key(id);

25、删除外键

alter table test drop foreign key FK_XXX;

26、QPS

SHOW GLOBAL STATUS LIKE 'Questions';
SHOW GLOBAL STATUS LIKE 'Uptime';
Questions/Uptime

27、TPS

SHOW GLOBAL STATUS LIKE 'Com_commit';
SHOW GLOBAL STATUS LIKE 'Com_rollback';
SHOW GLOBAL STATUS LIKE 'Uptime';
(Com_commit + Com_rollback)/Uptime

27、导出

select * from MacConfig into outfile '/tmp/MacConfig.sql' fields terminated by ',' lines terminated by '\n';

28、导入

load data infile '/tmp/MacConfig.sql' into table MacConfig fields terminated by ',' lines terminated by '\n';

29、清理binlog

PURGE BINARY LOGS TO 'XXX';

PURGE BINARY LOGS BEFORE '2017-11-09 00:00:00';

30、外键隔离级别等信息

select @@FOREIGN_KEY_CHECKS;
select @@global.tx_isolation,@@tx_isolation;  
select @@character_set_database;
select @@GLOBAL.sql_mode;

原文发布于微信公众号 - MYSQL轻松学(learnmysql)

原文发表时间:2017-11-16

本文参与腾讯云自媒体分享计划,欢迎正在阅读的你也加入,一起分享。

发表于

我来说两句

0 条评论
登录 后参与评论

相关文章

来自专栏PhpZendo

使用 MySQL Scheduler 和 Event 周期性创建数据表

使用 MySQL Scheduler 和 Event 周期性创建数据表,下面提供的是按月建表计划任务及事件通过 ON SCHEDULE EVERY 1 MINU...

2002
来自专栏Java呓语

第13.1.1章 语法解释ALTER DATABASE

ALTER DATABASE 允许修改数据库的特征,所有关于数据库的特征都存储在db.opt文件中。你必须先具备该数据库的ALTER特权,才能完成对数据库的AL...

831
来自专栏数据和云

运维技巧 - 活用临时表隔离冷热数据

编辑手记:Oracle给了我们很多工具,在日常数据库管理中活用这些工具方可发挥最大效能。 作者简介: 张洪涛 富士康 DBA 在数据库监控过程中发现考勤数据...

4035
来自专栏测试开发架构之路

SQL语句之奇形怪状的冷门函数

lag() over() SELECT C.*,LAG(C.column,1) OVER(ORDER BY C.column) FROM Table C; 第...

2963
来自专栏撸码那些事

MySQL——索引优化实战

上篇文章中介绍了索引的基本内容,这篇文章我们继续介绍索引优化实战。在介绍索引优化实战之前,首先要介绍两个与索引相关的重要概念,这两个概念对于索引优化至关重要。

1432
来自专栏数据库新发现

CTAS、Nologging以及数据库运行模式

http://www.itpub.net/showthread.php?threadid=242761

1274
来自专栏乐沙弥的世界

Oracle 分区索引

    分区索引(或索引分区)主要是针对分区表而言的。随着数据量的不断增长,普通的堆表需要转换到分区表,其索引呢,则对应的转换到分区索引。分区索引的好处是显而易...

2961
来自专栏pangguoming

oracle的行级触发器使用

行级触发器: 当触发器被触发时,要使用被插入、更新或删除的记录中的列值,有时要使用操作前、后列的值. :NEW 修饰符访问操作完成后列的值 :OLD 修饰符访问...

3345
来自专栏PHP在线

MySQL DELETE语句和TRUNCATE TABLE语句的区别

MySQL DELETE语句和TRUNCATE TABLE语句功能相似,但是二者究竟有何区别呢?下文就将为您分析MySQL DELETE语句和TRUNCATE ...

38614
来自专栏性能与架构

Mysql DISTINCT的实现思路

DISTINCT实际上和GROUP BY操作非常相似,只不过是在GROUP BY之后的每组中只取出一条记录而已 所以,DISTINCT的实现方式和GROUP B...

3787

扫码关注云+社区

领取腾讯云代金券