April 20, 2014

How InnoDB promotes UNIQUE constraints

The other day I was running pt-duplicate-key-checker on behalf of a customer and noticed some peculiar recommendations on an InnoDB table with an odd structure (no PRIMARY key, but multiple UNIQUE constraints). This got me thinking about how InnoDB promotes UNIQUE constraints to the role of PRIMARY KEYs. The documentation is pretty clear: [DOCS] When […]

Want to archive tables? Use Percona Toolkit’s pt-archiver

Percona Toolkit’s pt-archiver is one of the best utilities to archive the records from large tables to another tables or files. One interesting thing is that pt-archiver is a read-write tool. It deletes data from the source by default, so after archiving you don’t need to delete it separately. As it is done by default, you […]

Schema changes – what’s new in MySQL 5.6?

Among many of the improvements you can enjoy in MySQL 5.6, there is one that addresses a huge operational problem that most DBAs and System Administrators encounter in their life: schema changes. While it is usually not a problem for small tables or those in early stages of product life cycle, schema changes become a […]

Limited disk space? Compact backups with Percona Xtrabackup 2.1

One very interesting feature, “Compact Backup,” is introduced in Percona XtraBackup 2.1. You can run “compact backups” with the  –compact option, which is very useful for those who have limited disk space to keep the database backup. Now let’s first understand how it works. When we are using –compact option with Innobackupex, it will omit the secondary […]

Implementing SchemaSpy in your MySQL environment

Lately I have been working with a set of customers on a longer term basis which has given me time to explore new tools using their environments.  One tool that I am finding very helpful is called SchemaSpy. SchemaSpy is a Java-based tool (requires Java 5 or higher) that analyzes the metadata of a schema in […]

Is Synchronous Replication right for your app?

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 […]

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

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 […]

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

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 […]

Sphinx search performance optimization: attribute-based filters

One of the most common causes of a poor Sphinx search performance I find our customers face is misuse of search filters. In this article I will cover how Sphinx attributes (which are normally used for filtering) work, when they are a good idea to use and what to do when they are not, but […]