在MySQL的客户端中通过show [full] processlist可以看到当前所有线程，以及线程的状态，当然也包括执行中的sql，但是显示的语句不完全，并且有很多空闲线程会造成干扰。

这里要介绍一个非常好用的开源工具innotop（sourceforge已经被墙了，要过去先找梯子），由于是用perl写的，所以需要安装相关的perl模块，包括DBI，DBD::mysql，Term::ReadKey和Time::HiRes，这些模块都可以到CPAN找到。

用innotop的Q模式则可以完美的解决获取当前运行的SQL的问题。innotop -m Q 或者innotop进入后再按shift+q进入Query list模式：

Query List (? for help) mysql01, 75+03:16:16, 774.20 QPS, 83 thd, 5.1.24-rc-log

CXN    When   Load  QPS     Slow  QCacheHit  KCacheHit  BpsIn    BpsOut
my120  Now    0.00  774.20     0     40.22%    100.00%  207.98k    1.46M
my120  Total  0.00  212.69     2     29.70%    100.00%   56.90k  402.15k

CXN     Cmd    ID      User    Host           DB      Time   Query
mysql01   Query   20936  poster  192.168.1.1    poster  00:00  select a.poster_id,
a.pic_id, a.gmt_create, a.gmt_modified, a.url, a.no

然后按e并输入thread ID显示执行计划或者按f显示完整sql语句，或者按o显示系统优化过的语句（需要MySQL的版本支持EXPLAIN EXTENDED）。个人感觉，还是e最有用，其他两个选项，则有点鸡肋了。

Query List (? for help)  mysql01, 75+03:16:16, 774.20 QPS, 83 thd, 5.1.24-rc-log
EXPLAIN PARTITIONS
select a.poster_id, a.pic_id, a.gmt_create, a.gmt_modified, a.url, a.notes,
a.type, a.indexed, a.user_id, a.user_nick, b.pic_path from poster.poster_pic a
inner join poster.picture b on (a.pic_id = b.id) where a.poster_id = 3390
order by a.indexed
______________ Sub-Part 1 ______________  ________ Sub-Part 1 ________
Select Type: SIMPLE                       Select Type: SIMPLE
      Table: a                                  Table: b
 Partitions:                               Partitions:
       Type: ref                                 Type: eq_ref
 Poss. Keys: PRIMARY                       Poss. Keys: PRIMARY
      Index: PRIMARY                            Index: PRIMARY
 Key Length: 4                             Key Length: 8
  Index Ref: const                          Index Ref: poster.a.PIC_ID
  Row Count: 14                             Row Count: 1
    Special: Using where; Using filesort      Special:                

Press e to explain, f for full query, o for optimized query

Query List (? for help)  mysql01, 75+03:16:16, 774.20 QPS, 83 thd, 5.1.24-rc-log
select a.poster_id, a.pic_id, a.gmt_create, a.gmt_modified, a.url, a.notes,
a.type, a.indexed, a.user_id, a.user_nick, b.pic_path from poster.poster_pic a
inner join poster.picture b on (a.pic_id = b.id) where a.poster_id = 3390
order by a.indexed

Press e to explain, f for full query, o for optimized query

Query List (? for help)  mysql01, 75+03:16:16, 774.20 QPS, 83 thd, 5.1.24-rc-log
select a.poster_id, a.pic_id, a.gmt_create, a.gmt_modified, a.url, a.notes,
 a.type, a.indexed, a.user_id, a.user_nick, b.pic_path from poster.poster_pic a
 inner join poster.picture b on (a.pic_id = b.id) where a.poster_id = 3390
order by a.indexed

Note:
select `poster`.`a`.`POSTER_ID` AS `poster_id`,`poster`.`a`.`PIC_ID` AS
`pic_id`,`poster`.`a`.`GMT_CREATE` AS `gmt_create`,`poster`.`a`.`GMT_MODIFIED`
AS `gmt_modified`,`poster`.`a`.`URL` AS `url`,`poster`.`a`.`NOTES` AS
`notes`,`poster`.`a`.`TYPE` AS `type`,`poster`.`a`.`INDEXED` AS
`indexed`,`poster`.`a`.`USER_ID` AS `user_id`,`poster`.`a`.`user_nick` AS
`user_nick`,`poster`.`b`.`PIC_PATH` AS `pic_path`
from `poster`.`poster_pic` `a`  join `poster`.`picture` `b`
 where ((`poster`.`b`.`ID` = `poster`.`a`.`PIC_ID`)
and (`poster`.`a`.`POSTER_ID` = 3390)) order by `poster`.`a`.`INDEXED`

Press e to explain, f for full query, o for optimized query

那么innotop是从哪里取的数据呢？应该是通过information_schema.processlist来获得完整的sql语句，并且根据COMMAND来过滤掉空闲线程的。

mysql> desc information_schema.processlist;
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| ID      | bigint(4)   | NO   |     | 0       |       |
| USER    | varchar(16) | NO   |     |         |       |
| HOST    | varchar(64) | NO   |     |         |       |
| DB      | varchar(64) | YES  |     | NULL    |       |
| COMMAND | varchar(16) | NO   |     |         |       |
| TIME    | bigint(7)   | NO   |     | 0       |       |
| STATE   | varchar(64) | YES  |     | NULL    |       |
| INFO    | longtext    | YES  |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
8 rows in set (0.00 sec)

--EOF--

来自：http://rdc.taobao.com/blog/dba/html/182_how_mysql_get_current_running_sql_statements.html

分类： 数据库开发 数据仓库 Web技术