Cartesian Products usually don't provide useful information and often result in mistakes that can hurt your database developer career. Learn to spot Cartesian Joins and banish them from your SELECT queries forever.

How long it may take MySQL with Innodb tables to shut down ? It can be quite a while.
In default configuration innodb_fast_shutdown=ON the main job Innodb has to do to complete shutdown is flushing dirty buffers. The number of dirty buffers in the buffer pool varies depending on innodb_max_dirty_pages_pct [...]

Ignacio Nin and I (mostly Ignacio) have worked together to create tcprstat[1], a new tool that times TCP requests and prints out statistics on them. The output looks somewhat like vmstat or iostat, but we’ve chosen the statistics carefully so you can compute meaningful things about your TCP traffic.
What is this good for? [...]

The SELECT statement is without question the most complex amongst MySQL's data manipulation statements. This article covers the syntax of the SELECT statement, exploring its many optional clauses.

I recently encountered an interesting case. A customer reported that mysqld crashed on start on OpenSUSE 11.2 kernel 2.6.31.12-0.2-desktop x86_64   with 96 GB RAM when the innodb_buffer_pool_size was set to anything more than 62 GB. I decided to try it with 76 GB. The error message was an assert due to a failed malloc() [...]

This post is the fourth of a series that started here.
From the previous of this series, we now have resources configured but instead of starting MySQL, Pacemaker invokes a script to start (or restart) the EC2 instance running MySQL. This blog post describes the instance restart script. Remember, I am more a DBA [...]

Four Perconians (perconites?) will be at OpenSQL Camp in Sankt Augustin, Germany this weekend presenting talks on:

Recovery of Lost or Corrupted InnoDB Tables
Keep your MySQL backend online no matter what
XtraDB — InnoDB on steroids
Xtrabackup for MySQL

If you would like to stop by and say hello, we are Aleksandr, Istvan, Morgan and Aurimas (pictures here).
If you [...]

We’re opening up registration for our new training courses today.  In short: we are moving from two days to a new four-day format.  The new additions are created by:

Splitting our current InnoDB day in half. We now have one day for DBAs, and one day just on InnoDB topics.
A new Operations Day – covering how [...]

Increasingly, enterprises are looking at cloud services such as Amazon Web Services for their deployments. Datacenter virtualization is much more sophisticated than its desktop counterpart is, providing a whole suite of tools that allow you to control every aspect of your deployments. Join Sean Hull as he explores the MySQL - Amazon EC2 solution.

Recently I had the opportunity to do some testing on a large data set against two MySQL column-store storage engines. I’d like to note that this effort was sponsored by Infobright, but this analysis reflects my independent testing from an objective viewpoint.
I performed two different types of testing. The first focused on core [...]

In some environments using a distro package management system may* provide benefits including handling dependencies and providing a simpler approach when there are no dedicated DBA or SA resources.
However, the incorrect use can result in pain and in this instance production downtime. Even with dedicated resources at an unnamed premium managed hosting provider, the [...]

If you read Percona’s whitepaper on Goal-Driven Performance Optimization, you will notice that we define performance using the combination of three separate terms. You really want to read the paper, but let me summarize it here:

Response Time – This is the time required to complete a desired task.
Throughput – Throughput is measured in tasks [...]

Unlike previous years when the number of conferences with MySQL content diminishes after the O’Reilly MySQL and OSCON conferences (Open SQL Camp excluded), this year has a lot on offer.
This month:

Open SQL Camp Europe Edition on Saturday 21st and Sunday 22nd August

Upcoming next month in September:

MySQL Sunday at Oracle Open World on September 18 in [...]

A common observation for many LAMP stack products is the use of poor MySQL security practices. Even for more established products such as Wordpress don’t always assume that the provided documentation does what it best for you. As per my earlier posts where I detailed installation instructions and optimal permissions for both WordPress [...]

Within a few hours my post Installing Mediawiki on Oracle Enterprise Linux LAMP stack got 5 negative votes.
Wow, I’d be glad if these people could felt so passionately about all the other CRUD on Planet MySQL that has ZERO to do actually do with MySQL.
Using a LAMP product, and providing instructions for operation [...]

A company wiki can be easily configured in under 10 minutes using Mediawiki the open source LAMP software that powers the top 10 website Wikipedia.
A company wiki is an ideal means for a centralized and user contributed documentation system. The following steps show you how to download, configure and get your Mediawiki site operational.
Software Pre-Requisites

Installing [...]

Knowing and working with master-master replication and keeping a true hot standby is very important, especially when your business requires a fast failover with the least amount of downtime. This article focuses on the wonderful world of multi-master replication. Knowing how to setup and implement multi-master replication is the next step to faster, automated failover.

In the last few days there has been some press of the Augen gentouch 7″ Tablet. A new cheap tablet that is running Android 2.1.

Image from http://android-devices.net
There were a few primary motivations for getting one, the first being price, at $150 I consider cheap for a small tablet, and second it runs Android, [...]

A couple of weeks ago one of my colleagues and I worked on a data corruption case that reminded me that sometimes people make unsafe assumptions without knowing it. This one involved SAN snapshotting that was unsafe.
In a nutshell, the client used SAN block-level replication to maintain a standby/failover MySQL system, and there was [...]

There is a lot of discussions whenever running MySQL storing data on NFS is a good idea. There is a lot of things for and against this and this post is not about them.
The fact is number of people run their databases on NetApp and other forms of NFS storage and this post is about [...]

I get asked this question often. It was mentioned again recently in a NYTECH executive breakfast with RedHat CIO Lee Congdon.
The short answer is No.
There is clear evidence that in the short to medium term Oracle will continue to promote and enhance MySQL. Some of these indicators include:

EU 10 point commitment in December 2009 – [...]

I will be joining a great list of quality speakers including John Allspaw, Theo Schlossnagle, Rasmus Lerdorf and Tom Cook at Surge 2010 in Baltimore, Maryland on Thu 30 Sep, and Fri Oct 1st 2010.
My presentation on “The most common MySQL scalability mistakes, and how to avoid them.” will include discussing various experiences observed [...]

I recently gave a webinar to the LAOUC and NZOUG user groups on MySQL Idiosyncrasies that BITE.
For the benefit of many viewers that do not use English as a first language my slides include some additional information from my ODTUG Kaleidoscope presentation in June.
Thanks to Francisco Munoz Alvarez for organizing.
MySQL Idiosyncrasies That Bite 2010.07
View [...]

Rob Gravelle explores the MySQL UPDATE statement, which is used to modify existing records in a table. Among its many features, he looks at how to update multiple tables, avoiding mistakes, and how to limit how many rows are updated.

I recently had a run-in with very popular PHP ecommerce package which makes me want to voice a recurring mistake I see in how many web applications are architected.
What is that mistake?

The ecommerce package I was working with depended on caching.  Out of the box it couldn’t serve 10 pages/second unless I enabled some features [...]

If you have not looked at my recent presentation that I presented at ODTUG Kaleidoscope 2010, then feel free to join me on Tuesday, July 27, 2010 6:00 PM – 7:00 PM EDT tomorrow at 5pm EDT when I will giving a webinar on this talk. You can register online at https://www1.gotomeeting.com/register/730452824

The IOUG Online Education Series: Get Real with Upgrades will include next week 3 different MySQL webinars. These are:

MySQL 5.1: Why and How to Upgrade by Sheeri Cabral on Tuesday, July 27, 12:00 p.m. – 1:00 p.m. CT
MySQL Upgrades With No Downtime by Sean Hull on Wednesday, July 28, 12:00 p.m. – 1:00 [...]

Learn how you too can stamp out common database errors and learn a lot about relational databases along the way. 'Ambiguous Groups' is extracted from 'SQL Antipatterns', published by the Pragmatic Bookshelf.

It is easy for MySQL replication to become bottleneck when Master server is not seriously loaded and the more cores and hard drives the get the larger the difference becomes, as long as replication
remains single thread process. At the same time it is a lot easier to optimize your system when your replication [...]

Multi-master MySQL, with the MMM management software brings a whole host of new features, and manageability to your MySQL deployments.   Run backups, alter tables, perform upgrades all without slowing down your production users.
Read more at Database Journal – Using Multi-master MySQL To Get A Leg Up On Database Performance