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 [...]
MySQL caching methods and tips
“The least expensive query is the query you never run.” Data access is expensive for your application. It often requires CPU, network and disk access, all of which can take a lot of time. Using less computing resources, particularly in the cloud, results in decreased overall operational costs, so caches provide real value by avoiding [...]
InnoDB Flushing: Theory and solutions
I mentioned problems with InnoDB flushing in a previous post. Before getting to ideas on a solution, let’s define some terms and take a look into theory. The two most important parameters for InnoDB performance are innodb_buffer_pool_size and innodb_log_file_size. InnoDB works with data in memory, and all changes to data are performed in memory. In [...]
How Percona strives to remain neutral and independent
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 [...]
Data Corruption, DRBD and story of bug
Working with customer, I faced pretty nasty bug, which is actually not rare situation , but in this particular there are some lessons I would like to share. The case is pretty much described in bug 55981, or in pastebin. Everything below is related to InnoDB-plugin/XtraDB, but not to regular InnoDB ( i.e in MySQL [...]
Recovery beyond data restore
Quite frequently I see customers looking at recovery as on ability to restore data from backup which can be far from being enough to restore the whole system to operating state, especially for complex systems. Instead of looking just at data restore process you better look at the whole process which is required to bring [...]
10+ Ways to Crash or Overload MySQL
People are sometimes contacting me and asking about bugs like this which provide a trivial way to crash MySQL to the user with basic privileges and asking me what to do. My answer to them is – there is nothing new to it and they just sit should back and relax Really – there are [...]
Undo area size restriction needed for Innodb
As you can read from my Innodb Architecture and Performance Optimization presentation Innodb automatically manages undo area in system tablespace so you never need to care about it. I present it as positive feature reducing administration effort needed but it also can cause a troubles as it happened for me today: InnoDB: 11 transaction(s) which [...]

