一台服务器上的MySQL比另一台服务器慢10倍

Question

I have a live server and my dev server, and I am finding that queries on my LIVE (not dev) server run 10x slower, even though the live server is more powerful and they are both running comparable load. It's not a database structure thing because I load the backup from the live server into my dev server.

Does anybody have any ideas on where I could look for the discrepancy? Could it be a MySQL config thing? Where should I start looking?

Live Server:

mysql> SELECT count(`Transaction`.`id`) as count, sum(`Transaction`.`amount`) as sum, sum(Transaction.citiq_margin+rounding + Transaction.citiq_margin_vat) as revenue FROM `transactions` AS `Transaction` LEFT JOIN `meters` AS `Meter` ON (`Transaction`.`meter_id` = `Meter`.`id`) LEFT JOIN `units` AS `Unit` ON (`Meter`.`unit_id` = `Unit`.`id`) WHERE (NOT (`Unit`.`building_id` IN ('1', '85')) AND NOT (`Transaction`.`state` >= 90)) AND DAY(`Transaction`.`created`) = DAY(NOW()) AND YEAR(`Transaction`.`created`) = YEAR(NOW()) AND (MONTH(`Transaction`.`created`)) = MONTH(NOW());
+-------+---------+---------+
| count | sum     | revenue |
+-------+---------+---------+
|   413 | 3638550 |  409210 |
+-------+---------+---------+
1 row in set (2.62 sec)

[root@mises ~]# uptime
 17:11:57 up 55 days, 1 min,  1 user,  load average: 0.45, 0.56, 0.60

Dev Server (result count is different because of slight time delay from backup):

mysql>  SELECT count(`Transaction`.`id`) as count, sum(`Transaction`.`amount`) as sum, sum(Transaction.citiq_margin+rounding + Transaction.citiq_margin_vat) as revenue FROM `transactions` AS `Transaction` LEFT JOIN `meters` AS `Meter` ON (`Transaction`.`meter_id` = `Meter`.`id`) LEFT JOIN `units` AS `Unit` ON (`Meter`.`unit_id` = `Unit`.`id`) WHERE (NOT (`Unit`.`building_id` IN ('1', '85')) AND NOT (`Transaction`.`state` >= 90)) AND DAY(`Transaction`.`created`) = DAY(NOW()) AND YEAR(`Transaction`.`created`) = YEAR(NOW()) AND (MONTH(`Transaction`.`created`)) = MONTH(NOW());
+-------+---------+---------+
| count | sum     | revenue |
+-------+---------+---------+
|   357 | 3005550 |  338306 |
+-------+---------+---------+
1 row in set (0.22 sec)

[www@smith test]$ uptime
 18:11:53 up 12 days,  1:57,  4 users,  load average: 0.91, 0.75, 0.62

Live Server (2 x Xeon Quadcore):

processor       : 7
vendor_id       : GenuineIntel
cpu family      : 6
model           : 44
model name      : Intel(R) Xeon(R) CPU           E5620  @ 2.40GHz
stepping        : 2
cpu MHz         : 2395.000
cache size      : 12288 KB
physical id     : 0
siblings        : 8
core id         : 10
cpu cores       : 4

Dev Server (1 x Quadcore)

processor       : 3
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Intel(R) Core(TM)2 Quad CPU    Q8300  @ 2.50GHz
stepping        : 10
microcode       : 0xa07
cpu MHz         : 1998.000
cache size      : 2048 KB
physical id     : 0
siblings        : 4
core id         : 3
cpu cores       : 4

Live Server:

1. CentOS 5.7
2. MySQL ver 5.0.95

Dev Server:

1. ArchLinux
2. MySQL ver 5.5.25a

Answer 1

The obvious first thing to check would be your MySql configuration file to make sure you are utilizing an appropriate amount of memory for queries.. such as key_buffer, sort_buffer, etc... There are far smarter people than me out there who have entire blogs dedicated to configuring MySql.

You can also prepend your query with "explain" to see what is taking the most time... but that might just be something for general use later on.

In reality, your "live" server has caching capabilities and twice the number of cores to make these queries, and it likely has enough horsepower and memory to explain the difference in query times between the servers.

Answer 2

So, I ran the same database and queries on a Virtual Machine running Centos, 1 CPU and 512MB of memory: it provides the answer to that query in 0.3 seconds; system load is 0.4 :/

The only real difference seems to be that I am running Mysql 5.5 on that server. And it seems that there really is a 10x performance improvement in my case from Mysql 5.0 to Mysql 5.5.

I will only know for sure once I have migrated my live servers from Mysql 5.0 to Mysql 5.5, I will confirm the results once I have done that.