You know how in addition to the main movie you have extras on the DVD. Extra commentary, bloopers, extra scenes, etc? Well welcome the Tyrant extras. With my previous blog posts I was trying to set-up a case for looking at NOSQL tools, and not meant to be a decision making tool. Each solution has [...]
InnoDB: look after fragmentation
November 5, 2009 By 12 Comments
One problem made me puzzled for couple hours, but it was really interesting to figure out what’s going on. So let me introduce problem at first. The table is
1 2 3 4 5 6 7 8 | CREATE TABLE `c` ( `tracker_id` int(10) unsigned NOT NULL, `username` char(20) character set latin1 collate latin1_bin NOT NULL, `time_id` date NOT NULL, `block_id` int(10) unsigned default NULL, PRIMARY KEY (`tracker_id`,`username`,`time_id`), KEY `block_id` (`block_id`) ) ENGINE=InnoDB |
Table has 11864696 rows and takes Data_length: 698,351,616 bytes on disk The problem is that after restoring table from mysqldump, the query that scans data [...]
Faster MySQL failover with SELECT mirroring
February 1, 2009 By 9 Comments
One of my favorite MySQL configurations for high availability is master-master replication, which is just like normal master-slave replication except that you can fail over in both directions. Aside from MySQL Cluster, which is more special-purpose, this is probably the best general-purpose way to get fast failover and a bunch of other benefits (non-blocking ALTER [...]
How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
Our customers or prospective customers often ask us how we do a performance audit (it’s our most popular service). I thought I should write a blog post that will both answer their question, so I can just reply “read all about it at this URL” and share our methodology with readers a little bit. This [...]
A common problem when optimizing COUNT()
September 20, 2008 By 18 Comments
When optimizing queries for customers, the first thing I do with a slow query is figure out what it’s trying to do. You can’t fully optimize a query unless you know how to consider alternative ways to write it, and you can’t do that unless you know what the query “means.” I frequently run into [...]
Can MySQL temporary tables be made safe for statement-based replication?
May 26, 2008 By 8 Comments
A while ago I wrote about how to make MySQL replication reliable, part of which is to eliminate temporary tables. The idea is this: if a slave is stopped (or crashed) while a temporary table is open and is then restarted, the temporary table doesn’t exist anymore, and the slave will have problems trying to [...]
