Percona is glad to announce the release of Percona Server 5.5.25a-27.1 on July 21st, 2012 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.5.25a, including all the bug fixes in it, Percona Server 5.5.25a-27.1 is now the current stable release in the 5.5 series. All of Percona‘s software is open-source and free, all the details of the release can [...]
MySQL Upgrade Webinar Questions Followup
I did a Webinar about MySQL Upgrade – Best Practices Yesterday and there were some questions we could not answer during Webinar, following Jay’s Lead I decided to post them as a Blog Post. Q: Can you go directly MySQL 5.0 to 5.5 for MyISAM tables? MyISAM have not been getting any significant development since [...]
On Character Sets and Disappearing Tables
The MySQL manual tells us that regardless of whether or not we use “SET FOREIGN_KEY_CHECKS=0″ before making schema changes, InnoDB will not allow a column referenced by a foreign key constraint to be modified in such a way that the foreign key will reference a column with a mismatched data type. For instance, if we [...]
Training in London next week
I’m going to deliver MySQL Training next week (May 21-24) in London. This is a rare opportunity as I do not personally deliver a lot of Training, especially outside of US. There are still some places left if you want to sign up. You will also get a signed copy of High Performance MySQL 3rd [...]
Best kept MySQLDump Secret
Many people use mysqldump –single-transaction to get consistent backup for their Innodb tables without making database read only. In most cases it works, but did you know there are some cases when you can get table entirely missing from the backup if you use this technique ? The problem comes from the fact how MySQL’s [...]
Free ticket to MySQL User Conference on SF Meetup with talk “Percona XtraDB Cluster”
Just a reminder that I will be giving a talk “Percona XtraDB Cluster” on coming San Francisco MySQL Meetup, next Wednesday, March-21, 2012. Along with talk I will give away one full ticket (tutorials + sessions + expo hall) to Percona Live MySQL User Conference 2012 and three copies our new book “High Performance MySQL, [...]
My talks on PL MySQL Conference (+free book inside)
On coming PL MySQL conference 2012 I will give one tutorial: Percona XtraBackup: install, usage, tricks. This tutorial I will do in joint with Alexey Kopytov, the lead developer of Percona XtraBackup. Our intent is to provide the comprehensive overview of the XtraBackup architecture and features, and we will touch future roadmap. This is all [...]
When EXPLAIN estimates can go wrong!
I have been working with a few customer cases and one interesting case popped up. The customer was facing a peculiar problem where the rows column in the EXPLAIN output of the query was totally off. The actual number of rows was 18 times more than the number of rows reported by MySQL in the [...]
SELECT UNION Results INTO OUTFILE
Here’s a quick tip I know some of us has overlooked at some point. When doing SELECT … UNION SELECT, where do you put the the INTO OUTFILE clause? On the first SELECT, on the last or somewhere else? The manual has the answer here, to quote: Only the last SELECT statement can use INTO [...]
Recovering Linux software RAID, RAID5 Array
Dealing with MySQL you might need to deal with RAID recovery every so often. Sometimes because of client lacking the proper backup or sometimes because recovering RAID might improve recovery, for example you might get point in time recovery while backup setup only takes you to the point where last binary log was backed up. [...]

