May 23, 2013

Galera Flow Control in Percona XtraDB Cluster for MySQL

May 2, 2013 By 5 Comments

Last week at Percona Live, I delivered a six-hour tutorial about Percona XtraDB Cluster (PXC) for MySQL.  I actually had more material than I covered (by design), but one thing I regret we didn’t cover was Flow control.  So, I thought I’d write a post covering flow control because it is important to understand. What [...]

Filed Under: Insight for DBAs, Percona Live, XtraDB Cluster Tagged With: , , ,

Understanding the maximum number of columns in a MySQL table

April 8, 2013 By 5 Comments

This post was initially going to be two sets of polls: “What is the maximum number of columns in MySQL?” and “What is the minimum maximum number of columns in MySQL?”. Before you read on, ponder those questions and come up with your own answers… and see if you’re right or can prove me wrong! [...]

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MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark

March 11, 2013 By 7 Comments

So far most of the benchmarks posted about MySQL 5.6 use the sysbench OLTP workload.  I wanted to test a set of queries which, unlike sysbench, utilize joins.  I also wanted an easily reproducible set of data which is more rich than the simple sysbench table.  The Star Schema Benchmark (SSB) seems ideal for this. [...]

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InnoDB Full-text Search in MySQL 5.6: Part 2, The Queries!

March 4, 2013 By 7 Comments

This is part 2 in a 3 part series. In part 1, we took a quick look at some initial configuration of InnoDB full-text search and discovered a little bit of quirky behavior; here, we are going to run some queries and compare the result sets. Our hope is that the one of two things [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL Tagged With: , , , , ,

InnoDB Full-text Search in MySQL 5.6 (part 1)

February 26, 2013 By 1 Comment

I’ve never been a very big fan of MyISAM; I would argue that in most situations, any possible advantages to using MyISAM are far outweighed by the potential disadvantages and the strengths of InnoDB. However, up until MySQL 5.6, MyISAM was the only storage engine with support for full-text search (FTS). And I’ve encountered many [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL Tagged With: , , , , ,

Quickly finding unused indexes (and estimating their size)

December 5, 2012 By 2 Comments

I had a customer recently who needed to reduce their database size on disk quickly without a lot of messy schema redesign and application recoding.  They didn’t want to drop any actual data, and their index usage was fairly high, so we decided to look for unused indexes that could be removed. Collecting data It’s [...]

Filed Under: Insight for DBAs, MySQL, Percona Software

Knowing what pt-online-schema-change will do

November 1, 2012 By 1 Comment

pt-online-schema-change is simple to use, but internally it is complex.  Baron’s webinar about pt-online-schema-change hinted at several of the tool’s complexities.  Consequently, users often want to know before making changes what pt-online-schema-change will do when it runs.  The tool has two options to help answer this question: –dry-run and –print. When ran with –dry-run and –print, pt-online-schema-change changes nothing [...]

Filed Under: Insight for DBAs, Percona Software Tagged With:

Edge-case behavior of INSERT…ODKU

October 27, 2012 By 6 Comments

A few weeks back, I was working on a customer issue wherein they were observing database performance that dropped through the floor (to the point of an outage) roughly every 4 weeks or so. Nothing special about the environment, the hardware, or the queries; really, the majority of the database was a single table with [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL

Tools and Techniques for Index Design Webinar Questions Followup

October 4, 2012 By 5 Comments

I presented a webinar this week to give an overview of Tools and Techniques for Index Design. Even if you missed the webinar, you can register for it, and you’ll be emailed a link to the recording. I’d like to invite folks who are interested in tools for query optimization to attend the new Percona [...]

Filed Under: Insight for DBAs, Insight for Developers, MySQL

MySQL Indexing Best Practices: Webinar Questions Followup

August 16, 2012 By 4 Comments

I had a lot of questions on my MySQL Indexing: Best Practices Webinar (both recording and slides are available now) We had lots of questions. I did not have time to answer some and others are better answered in writing anyway. Q: One developer on our team wants to replace longish (25-30) indexed varchars with [...]

Filed Under: Insight for DBAs, MySQL
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