# Queries are super slow **URL:** \ **Category:** Other MySQL® Questions\ **Created:** [November 15, 2013, 12:57pm UTC](https://forums.percona.com/t/queries-are-super-slow/3092 "2013-11-15T12:57:00Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Jaan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/jaan/32/974_2.png) [@Jaan](https://forums.percona.com/u/Jaan)\ **Post date:** [November 15, 2013, 12:57pm UTC](https://forums.percona.com/t/queries-are-super-slow/3092/1 "2013-11-15T12:57:00Z")
Hey guys, I have a little problem. I have noticed that my queries are getting slower. Some update queries take about 48-50 seconds. Here’s how it looks: ![](https://us1.discourse-cdn.com/flex019/uploads/percona1/original/2X/6/628d9328f2e2661e4d3d6b69c98e035d9f368e4b.png) ```auto [root@db-1 ~]# tail /var/lib/mysql/mysql-slow.log # Time: 131113 17:09:48 # User@Host: J[J] @ [10.xxx.xxx.35] # Query_time: 61.013294 Lock_time: 0.000409 Rows_sent: 0 Rows_examined: 0 SET timestamp=1384380588; UPDATE b SET nf=0, lt=0, ud=1384380501, a='Trademarks' WHERE pid=36019263 AND l=3780235; # Time: 131113 17:09:49 # User@Host: J[J] @ [10.xxx.xxx.35] # Query_time: 18.145112 Lock_time: 0.000043 Rows_sent: 0 Rows_examined: 0 SET timestamp=1384380589; SELECT id FROM b WHERE pid=62921670 AND l=4808881; [root@db-1 ~]# ``` Here are the tables that are working together: ```auto mysql> explain b; +-------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------+--------------+------+-----+---------+----------------+ | id | int(30) | NO | PRI | NULL | auto_increment | | l | int(30) | NO | MUL | NULL | | | pid | int(30) | NO | MUL | NULL | | | nf | int(1) | NO | | NULL | | | lt | int(1) | NO | | NULL | | | fd | int(11) | NO | | NULL | | | ud | int(11) | NO | | NULL | | | le | int(1) | NO | MUL | NULL | | | a | varchar(150) | NO | | NULL | | +-------------+--------------+------+-----+---------+----------------+ 9 rows in set (0.00 sec) mysql> explain l; +------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+--------------+------+-----+---------+----------------+ | id | int(30) | NO | PRI | NULL | auto_increment | | u | varchar(255) | NO | UNI | NULL | | | ld | int(11) | YES | MUL | NULL | | +------------+--------------+------+-----+---------+----------------+ 3 rows in set (0.00 sec) ``` Here another explain: ```auto mysql> EXPLAIN SELECT id FROM b WHERE pid=8857932 AND l=3971963; +----+-------------+-----------+-------------+----------------+----------------+---------+------+------+-----------------------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-----------+-------------+----------------+----------------+---------+------+------+-----------------------------------------------------------+ | 1 | SIMPLE | b | index_merge | pid,l | pid,l | 4,4 | NULL | 1 | Using intersect(pid,l); Using where; Using index | +----+-------------+-----------+-------------+----------------+----------------+---------+------+------+-----------------------------------------------------------+ 1 row in set (0.00 sec) mysql> EXPLAIN SELECT nf=0, lt=0, ud=1384380501, a='Trademarks' FROM b WHERE pid=8857932 AND l=3971963; +----+-------------+-----------+-------------+----------------+----------------+---------+------+------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-----------+-------------+----------------+----------------+---------+------+------+----------------------------------------------+ | 1 | SIMPLE | b | index_merge | pid,l | pid,l | 4,4 | NULL | 1 | Using intersect(pid,l); Using where | +----+-------------+-----------+-------------+----------------+----------------+---------+------+------+----------------------------------------------+ mysql> EXPLAIN UPDATE b SET nf=0, lt=0, ud=1384474869, a='Order Status' WHERE pid=8858794 AND l=4997886; +----+-------------+-----------+-------------+----------------+----------------+---------+------+------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-----------+-------------+----------------+----------------+---------+------+------+----------------------------------------------+ | 1 | SIMPLE | b | index_merge | pid,l | pid,l | 4,4 | NULL | 1 | Using intersect(pid,l); Using where | +----+-------------+-----------+-------------+----------------+----------------+---------+------+------+----------------------------------------------+ 1 row in set (0.08 sec) ``` Here’s my config file: [URL][http://pastebin.com/HQFpxHSA[/URL]](http://pastebin.com/HQFpxHSA%5B/URL%5D) My server has: 2 x Intel E5506 2.1 Ghz 24GB RAM It would be wonderful if you guys could help me out. Thank you ---
**Author:** ![niljoshi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/niljoshi/32/16889_2.png) [@niljoshi](https://forums.percona.com/u/niljoshi)\ **Post date:** [November 27, 2013, 12:18am UTC](https://forums.percona.com/t/queries-are-super-slow/3092/2 "2013-11-27T00:18:23Z")
Hi, As per your explain plan of those queries, it looks like your queries are using proper indexes. Still if you want to check where exactly it’s taking time, I would suggest to use profiling. Please check below links for how to use it. [URL][http://dev.mysql.com/doc/refman/5.5/en/show-profile.html[/URL]](http://dev.mysql.com/doc/refman/5.5/en/show-profile.html%5B/URL%5D) [URL][http://www.mysqlperformanceblog.com/2012/02/20/how-to-convert-show-profiles-into-a-real-profile/[/URL]](http://www.mysqlperformanceblog.com/2012/02/20/how-to-convert-show-profiles-into-a-real-profile/%5B/URL%5D) ---
**Author:** ![wagnerbianchi](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/wagnerbianchi/32/802_2.png) [@wagnerbianchi](https://forums.percona.com/u/wagnerbianchi)\ **Post date:** [November 27, 2013, 4:15pm UTC](https://forums.percona.com/t/queries-are-super-slow/3092/3 "2013-11-27T16:15:15Z")
Jaan, Could you share with us the SHOW VARIABLES and SHOW STATUS of this MySQL instance in which you are running the query? Cheers, WB ---
**Author:** ![DenisM](https://avatars.discourse-cdn.com/v4/letter/d/e0b2c6/32.png) [@DenisM](https://forums.percona.com/u/DenisM)\ **Post date:** [November 29, 2013, 2:56am UTC](https://forums.percona.com/t/queries-are-super-slow/3092/4 "2013-11-29T02:56:46Z")
Do you have a RAID controller? Didn’t it fall into battery training cycle? Write-back cache maybe off in this case.