September 21, 2014

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 […]

How Much memory do you use to run MySQL

We have seen number of issues with MySQL Server related to amount of memory you have in the system – these range from problems with large size Query Cache to bad drop table performance with large Innodb Buffer Pool size. As such I wonder how much memory do we really use to run MySQL Server […]

Innodb Table Locks

Innodb uses row level locks right ? So if you see locked tables reported in SHOW ENGINE INNODB STATUS you might be confused and rightfully so as Innodb table locking is a bit more complicated than traditional MyISAM table locks. Let me start with some examples. First lets run SELECT Query:

As you 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 […]

Join Optimizations in MySQL 5.6 and MariaDB 5.5

This is the third blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. This blog post is targeted at the join related optimizations introduced in the optimizer. These optimizations are available in both MySQL 5.6 and MariaDB 5.5, and MariaDB 5.5 […]

Side load may massively impact your MySQL Performance

When we’re looking at benchmarks we typically run some stable workload and we run it in isolation – nothing else is happening on the system. This is not however how things happen in real world when we have significant variance in the load and many things can be happening concurrently. It is very typical to […]

Multiple purge threads in Percona Server 5.1.56 and MySQL 5.6.2

Part of the InnoDB duties, being an MVCC-implementing storage engine, is to get rid of–purge–the old versions of the records as they become obsolete.  In MySQL 5.1 this is done by the master InnoDB thread.  Since then, InnoDB has been moving towards the parallelized purge: in MySQL 5.5 there is an option to have a […]

Table locks in SHOW INNODB STATUS

Quite frequently I see people confused what table locks reported by SHOW INNODB STATUS really mean. Check this out for example:

This output gives us an impression Innodb has taken table lock on test/t1 table and many people tend to think Innodb in fact in some circumstances would abandon its row level locking and […]

Two Types of MySQL Users

In comments to my previous post I got number number of comments saying if MySQL would not have multiple storage engine interface it would not allow people to do various very cool stuff. And I agree with this. The question is how cool you want your database operation to be ? Visiting customers I see […]

The Doom of Multiple Storage Engines

One of the big “Selling Points” of MySQL is support for Multiple Storage engines, and from the glance view it is indeed great to provide users with same top level SQL interface allowing them to store their data many different way. As nice as it sounds the in theory this benefit comes at very significant […]