August 30, 2014

EXPLAIN EXTENDED can tell you all kinds of interesting things

While many people are familiar with the MySQL EXPLAIN command, fewer people are familiar with “extended explain” which was added in MySQL 4.1 EXPLAIN EXTENDED can show you what the MySQL optimizer does to your query. You might not know this, but MySQL can dramatically change your query before it actually executes it. This process […]

When (and how) to move an InnoDB table outside the shared tablespace

In my last post, “A closer look at the MySQL ibdata1 disk space issue and big tables,” I looked at the growing ibdata1 problem under the perspective of having big tables residing inside the so-called shared tablespace. In the particular case that motivated that post, we had a customer running out of disk space in his […]

Getting to know TokuDB for MySQL

During last April’s Percona Live MySQL Conference and Expo, TokuDB celebrated it’s first full-year as an open source storage engine. I still remember reading the official announcement and the expectations it created one year ago. The premises were very interesting as it had the potential of helping MySQL manage “big data” in a way InnoDB just […]

How to add an existing Percona XtraDB Cluster to Percona ClusterControl

In my last blog post I explained how to use Percona ClusterControl to create a new Percona XtraDB Cluster from scratch. That’s a good option when you want to create a testing environment in just some mouse clicks. In this case I’m going to show you how to add your existing cluster to Percona ClusterControl […]

How to monitor ALTER TABLE progress in MySQL

While working on a recent support issue as a Percona Support Engineer,  I got one question from a customer asking how to monitor ALTER TABLE progress. Actually, for MySQL 5.5 and prior versions, it’s quite difficult to ALTER the table in a running production environment especially for large tables (with millions records). Because it will rebuild and lock the table […]

Oracle’s Morgan Tocker opens up about MySQL development, MySQL 5.7

Today’s post features an interview with Morgan Tocker, MySQL community manager at Oracle. Morgan is an old friend of Percona, having worked here as director of MySQL training from 2009 to 2011. He’s also done stints at MySQL, Sun Microsystems and InPowered. You can follow his adventures at his blog, “Master MySQL.”  You can also […]

Calvin Sun on MySQL at Twitter, Percona Live 2014 and Facebook

Twitter’s Calvin Sun (@Calvinsun2012) is looking forward to the fast-approaching Percona Live MySQL Conference and Expo this April 1-4 in Santa Clara, Calif. He’ll be speaking, yes, but he’s also looking forward to learning from his peers – particularly those at Facebook. Both companies, he explained, are in the rather unique positions of unprecedented rapid […]

Beware of MySQL 5.6 server UUID when cloning slaves

The other day I was working on an issue where one of the slaves was showing unexpected lag. Interestingly with only the IO thread running the slave was doing significantly more IO as compared to the rate at which the IO thread was fetching the binary log events from the master. I found this out […]

How to recover table structure from .frm files with MySQL Utilities

Table structures are stored in .frm files and in the InnoDB Data Dictionary. Sometimes, usually in data recovery issues, we need to recover those structures to be able to find the lost data or just to recreate the tables. There are different ways to do it and we’ve already written about it in this blog. […]

Seconds_Behind_Master fluctuating wildly? Check for events caught in a loop

Recently I was working with a customer where we noticed that Seconds_Behind_Master fluctuating from an expected value of 0 seconds behind to a fairly high six figure value.  The servers were configured in a master-master relationship and used 5 figure server_id values, and we had just migrated this cluster from one data centre to another […]