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MySQL Feed

Oracle MySQL resources, news, and support articles.

Troubleshooting MySQL Memory Usage

One of the most painful troubleshooting tasks with MySQL is troubleshooting memory usage. The problem usually starts like this – you have configured MySQL to use reasonable global buffers, such as
innodb_buffer_size, key_buffer_size etc, you have reasonable amount of connections but yet MySQL takes much more memory than you would expect, causing swapping or other problems.

A Generic Normalizer step for Kettle


Kettle (a.k.a. Pentaho Data Integration) offers the standard Row Normalizer step to "unpivot" columns to rows. However, this step requires some configuration which presumes its input stream is static, and its structure is known. In this post, I explain how to construct a simple User-defined java class step that implements a generic Row Normalizer step that can unpivot an arbitrary input stream without manual configuration.


POSSCON, The Palmetto Open Source Software Conference, is being held next week on the 27th and 28th in Columbia, South Carolina. I was asked to combine two presentations so be prepared for MySQL Update & 20 MySQL Tips in 20 Minutes. This is a great conference in a thriving community.

Running Pentaho BI Server behind a proxy

To whom it may concern - a quick hands-on guide for running the Pentaho BI server behind a proxy


This post assumes you're running Ubuntu linux (or at least a Debian) and that you have both the apache Httpd server as well as the Pentaho BI server installed.

Apache HTTP Server

If you haven't got apache installed, this is your line:

$ sudo apt-get install apache2

You can then control the apache2 Http server using the apaceh2ctl script. For instance, to start it, do:

Announcing Percona Server 5.5.21-25.0

Percona is glad to announce the release of Percona Server 5.5.21-25.0 on March 20th, 2012. Downloads are available here and from the Percona Software Repositories.

Free webinar on monitoring MySQL

If you follow what Percona is up to, you might have noticed that I’ve created a set of high-quality monitoring and graphing plugins for MySQL and related systems. Currently they support Nagios and Cacti. I’ll give a free webinar on March 28th discussing these, and more broadly, discussing how to monitor MySQL successfully to avoid common problems like spammy alerts about nonexistent problems.

MySQL 5.6 too verbose when creating data directory

When I install a MySQL package using MySQL Sandbox, if everything goes smoothly, I get an informative message on standard output, and I keep working.

TIMESTAMP data types and CURRENT_TIMESTAMP attribute

In the yet to be released MySQL 5.6.6 DMR, there has been a change to the restriction of just one TIMESTAMP column with the DEFAULT CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP syntax. It is now possible for any TIMESTAMP to have either column defintion.

More information at

Free ticket to MySQL User Conference on SF Meetup with talk “Percona XtraDB Cluster”

Just a reminder that I will be giving a talk “Percona XtraDB Cluster” on coming San Francisco MySQL Meetup, next Wednesday, March-21, 2012. Along with talk I will give away one full ticket (tutorials + sessions + expo hall) to Percona Live MySQL User Conference 2012 and three copies our new book “High Performance MySQL, 3rd edition”.

ext4 vs xfs on SSD

As ext4 is a standard de facto filesystem for many modern Linux system, I am getting a lot of question if this is good for SSD, or something else (i.e. xfs) should be used.
Traditionally our recommendation is xfs, and it comes to known problem in ext3, where IO gets serialized per i_node in O_DIRECT mode (check for example Domas’s post)

However from the results of my recent benchmarks I felt that this should be revisited.

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