When setting up MySQL replication there are some things to remember. Although the setup is quite easy if you thoroughly read the documentation on MySQL's developer site you might still hit some issues.

We have quite a large scale replication setup (MySQL 4.1.12) with several hundred slaves. Today we saw a very strange situation: All of the slaves stopped replicating and claimed that a statement had been partially executed on the master side. The exact message was

Query partially completed on the master (error on master: 1053) and was aborted. There is a chance that your master is inconsistent at this point. If you are sure that your master is ok, run this query manually on the slave and then restart the slave with SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE;

The error code 1053 which means as much as "server shutdown".

We checked the master and could not …

Back in April MySQL had its yearly user's conference. Each year there are more users and more people to talk to, which means I get fewer chances to listen to any of the talks being presented. I did though take time out to listen to the talk on Second Life. I've been playing with BBS'es, Talkers, and other assorted digital online communities ever since I got my first modem. What fascinated me about Second Life was the prospect of it taking a shot at being the first "metaverse". I am a big fan of "Snow Crash" and would love to see that sort of environment spring to life. I work daily with friends and colleagues using IM and IRC, and any depth that can be added to those conversations is great as far as I am concerned.

I have also been fascinated with learning about how they are scaling with MySQL. Their design is fairly classic with replication, but what is interesting is to look and see how this is applied to a virtual …

Last Sunday I was heading out to a party when I overheard the conversation of "You shouldn't buy an iPod, they have a horrible interface". Now this always holds my interest since I do believe that the interface to my iPod could be a lot better. I stepped into the conversation and heard similar complaints as mine as to why the iPod was the wrong interface, and I also got an earfull on the "Geek Interface".

What is the "Geek Interface"? It is the interface that all geeks want.

It has a thousand buttons.
It will fetch RSS for you.
It reads your email.
It will control your remote vacuum cleaner/indestructible fighting robot.
It probably has an interface to a database (or this could be just because I work for MySQL).

Every geek wants one of these. They want it to be wearable, they want it to look cool.

The "geek …

I’ve been working on a new project to fulfill a specific need: consistent, fast, cheap, and flexible backups for MySQL, for all storage engines1. To that end I’m creating a tool called dbsnapper—a plugin-based backup tool. The tool itself is very basic and handles a few jobs: getting configuration information from the user, running through a “run sheet” of different configurable tasks, and reporting status and errors to the user.

The tasks then—the actual backup steps—are fully configurable, via plugins. In fact, the whole process isn’t even MySQL specific, and can potentially be used for PostgreSQL2 and other database as well. Remember the requirements for backups (above):

• Consistent—We need to do some locking inside MySQL to make sure that the backups are consistent, for both MyISAM and InnoDB tables. This generally means the FLUSH TABLES WITH READ LOCK command.
• Fast—There …

There’s been a lot of buzz lately about new storage engines (Solid’s SolidDB and Jim Starkey’s Falcon) being developed for MySQL. Quite a few people have asked me what I think about them, and if it’s really a seamless process to switch storage engines. Everybody still has Oracle’s acquisition of Innobase Oy fresh on their minds, so nobody is really terribly surprised by the recent announcements. As for my opinion on the matter, well, it’ll take some discussion. I was quoted in ComputerWorld’s article …

Are you a MySQL user? Have you tried 5.0? Did you notice that SHOW STATUS was giving you strange results?

Here’s the skinny: The SHOW STATUS command, which has been in MySQL, well forever, has had a long-standing feature request; to have the ability to report its metrics per-session. That functionality was added in MySQL 5.0, in the form of two new syntaxes: SHOW SESSION STATUS and SHOW GLOBAL STATUS to give the per-session and server-wide statistics, respectively. It’s great, and I’m happy to see it.

The problem comes in because of the default behaviour that was chosen for the basic SHOW STATUS with no SESSION or GLOBAL keyword—that is, the command that every MySQL DBA has been using for years—now defaults to per-session statistics.

Every tool, program, monitoring script, performance graph, etc., that uses SHOW STATUS (which is pretty much all of them) is broken in 5.0. Why? Well, for no reason, …

First, a bit of background information… MySQL has a variable called tmp_table_size which is used whenever a temporary table is needed for many types of operations, but it’s mainly used for ORDER BY and GROUP BY. The tmp_table_size variable (in correlation with the max_heap_table_size variable) decide at what point to convert an in-memory (that is, HEAP storage engine) temporary table to an on-disk (that is, MyISAM) one.

So, if the result of your query will end up greater than the lesser of tmp_table_size or max_heap_table_size, once it reaches that point, it will be automatically converted to a MyISAM table, on-disk (in tmpdir, incidentally).

Here’s a scenario: You have a SELECT query, nothing particularly special. It isn’t any more complex than another query on the same tables, but it performs a bit worse. You put some load on it, and it performs miserably, even putting the server in pain in the process. You check what’s …

No, this isn't about our multi-year extension of the InnoDB agreement with Oracle...  Instead, Apple has said that they will enable intel Mac users to run Windows.  Ok, they are doing it in an unsupported fashion with a bootloader called "Boot Camp" and customers need to install their own copy of Windows XP.  But still, it's a significant change of mind from Apple.  Well done guys!  Maybe Dvorak was right all along.

What's next?  Will Microsoft give a keynote at LinuxWorld?  Actually that happened this morning also, with Bill Hilf, General Manager of Platform Strategy.  …

The GUI tools team at MySQL has been working hard on a number of new releases including an update to the Migration Toolkit that provides many bug fixes as well as support for a broader range of source databases.  You can use the Migration Toolkit to go from any JDBC-supported database to MySQL 5.0 and there are also optimized migration modules for several versions back as well as the most recent versions of Oracle10g, Oracle XE, SQL Server 2005 and Access.

You can get the latest Migration Toolkit 1.0.25 below:

• MySQL: Migration Toolkit Downloads (1.0.25)
• MySQL: Migration …

This week at the EclipseCon in Santa Clara we announced that MySQL joined the Eclipse Foundation.  Admittedly, I wish we would have joined a long time ago (like maybe the first hundred times Mike and Donald asked us) but we finally got our ducks in a row.  To me Eclipse is one of the most successful and intriguing open source projects to date.  The entire process of open sourcing Eclipse was a masterpiece of strategy led by IBM that enabled them to create the best extensible tools platform.  There are really only two development tools platforms that matter: Eclipse and Visual Studio.  While both are open and extensible, only one of them is oopen source and cross-platform.

In fact, Eclipse has garnered support from more than 130 member firms and there are now more than 1000 Eclipse plug-ins and more than 60 projects …