I talk with lot of people who are really interested in Percona XtraDB Cluster (PXC) and mostly they are interested in PXC as a high-availability solution. But, what they tend not to think too much about is if moving from async to synchronous replication is right for their application or not. Facts about Galera replication [...]
Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs
February 23, 2012 By 3 Comments
LVM snapshots is one powerful way of taking a consistent backup of your MySQL databases – but did you know that you can now restore directly from a snapshot (and binary logs for point in time recovery) in case of that ‘Oops’ moment? Let me show you quickly how. This howto assumes that you already [...]
Eventual Consistency in MySQL
November 18, 2011 By 8 Comments
We’re told that foreign key constraints are the best way to enforce logical referential integrity (RI) in SQL, preventing rows from becoming orphaned. But then we learn that the enforcement of foreign keys incurs a significant performance overhead.1,2 MySQL allows us to set FOREIGN_KEY_CHECKS=0 to disable enforcement of RI when the overhead is too high. But [...]
Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
In the first part of this article I have showed how I align IO, now I want to share results of the benchmark that I have been running to see how much benefit can we get from a proper IO alignment on a 4-disk RAID1+0 with 64k stripe element. I haven’t been running any benchmarks [...]
Flexviews – part 3 – improving query performance using materialized views
April 4, 2011 By 20 Comments
Combating “data drift” In my first post in this series, I described materialized views (MVs). An MV is essentially a cached result set at one point in time. The contents of the MV will become incorrect (out of sync) when the underlying data changes. This loss of synchronization is sometimes called drift. This is conceptually [...]
How Percona strives to remain neutral and independent
March 21, 2011 By Leave a Comment
Many of the prominent companies in the MySQL ecosystem are Percona customers, including hardware manufacturers, software developers, hosted service providers, and appliance developers. We perform paid and unpaid research on their products, and we publish blog posts related to their products or services. Independence and objectivity are core Percona values. How do we balance the [...]
Percona Server 5.1.49-rel11.3
September 10, 2010 By 1 Comment
Dear Community, Percona Server version 5.1.49-rel11.3 is now available for download. The changes in this release include: New features Percona Server 5.1.49-rel11.3 is based on MySQL 5.1.49. A new variable was introduced: innodb_use_sys_stats_table. If ON, the table’s statistics are stored statically in the internal table SYS_STATS. The table is populated with the ANALYZE TABLE command. [...]
Two Types of MySQL Users
May 10, 2010 By 5 Comments
In comments to my previous post I got number number of comments saying if MySQL would not have multiple storage engine interface it would not allow people to do various very cool stuff. And I agree with this. The question is how cool you want your database operation to be ? Visiting customers I see [...]
SHOW OPEN TABLES – what is in your table cache
December 14, 2008 By 3 Comments
One command, which few people realize exists is SHOW OPEN TABLES – it allows you to examine what tables do you have open right now:
1 2 3 4 5 6 7 | mysql> show open tables from test; +----------+-------+--------+-------------+ | Database | Table | In_use | Name_locked | +----------+-------+--------+-------------+ | test | a | 3 | 0 | +----------+-------+--------+-------------+ 1 row in set (0.00 sec) |
Filtered MySQL Replication
November 7, 2007 By 8 Comments
To get this straight – I’m not a big fan of filtered or partial MySQL Replication (as of version MySQL 5.0) – there is enough gotchas with replication itself and getting things right with filtering can get quite bumpy road. In some applications however it is very helpful so lets see what one should do [...]
