April 23, 2014

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 […]

Hijacking Innodb Foreign Keys

I guess I’m first to post in 2012 so Happy New Year all blog readers ! Now back to HardCore MySQL business – foreign Keys. MySQL supported Foreign Keys for Innodb for many years, yet rudimentary support initially added in MySQL 3.23.44 have not been improved in new releases as much as I’d like. We […]

Hacking to make ALTER TABLE online for certain changes

Suppose you want to remove auto_increment from 100G table. No matter if it’s InnoDB or MyISAM, you’d usually ALTER TABLE huge_table CHANGE id id int(6) NOT NULL and then wait hours for table rebuild to complete. If you’re unlucky i.e. you have a lot of indexes and not too much RAM – you could end […]

MySQL Query Cache

MySQL has a great feature called “Query Cache” which is quite helpful for MySQL Performance optimization tasks but there are number of things you need to know. First let me clarify what MySQL Query Cache is – I’ve seen number of people being confused, thinking MySQL Query Cache is the same as Oracle Query Cache […]

Notes from the Newb

Notes from the Newb. I’m relatively new to MySQL having come from the world of embedded micro-databases, and though I’m pretty familiar with a number of database systems, I’ve discovered that I have a lot to learn about MySQL. As a new member to the Percona team, I thought I’d have an ongoing blog theme […]

Q&A: Common (but deadly) MySQL Development Mistakes

On Wednesday I gave a presentation on “How to Avoid Common (but Deadly) MySQL Development Mistakes” for Percona MySQL Webinars. If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions. I answered as many as we had time […]

The ARCHIVE Storage Engine – does it do what you expect?

Sometimes there is a need for keeping large amounts of old, rarely used data without investing too much on expensive storage. Very often such data doesn’t need to be updated anymore, or the intent is to leave it untouched. I sometimes wonder what I should really suggest to our Support customers. For this purpose, the […]

Multiple column index vs multiple indexes with MySQL 5.6

A question often comes when talking about indexing: should we use multiple column indexes or multiple indexes on single columns? Peter Zaitsev wrote about it back in 2008 and the conclusion then was that a multiple column index is most often the best solution. But with all the recent optimizer improvements, is there anything different with […]

How to recover an orphaned .ibd file with MySQL 5.6

A few years ago Yves Trudeau and Aleksandr Kuzminsky wrote posts about different ways for recovering orphaned .ibd files: Connecting orphaned .ibd files A recovery trivia or how to recover from a lost ibdata1 file Today I want to show you how to do that in more easy and quick way. In my example I’ll […]

Percona XtraDB Cluster: Setting up a simple cluster

Percona XtraDB Cluster (PXC) is different enough from async replication that it can be a bit of a puzzle how to do things the Galera way.  This post will attempt to illustrate the basics of setting up 2 node PXC cluster from scratch. Requirements Two servers (could be VMs) that can talk to each other. […]