Today I uploaded MySQL 5.1.23 to Debian experimental. It is currently waiting in the NEW queue for manual approval, because thanks to Monty Taylor the libndb parts are now in separate binary packages libndbclient3 and libndbclient-dev. Until it is getting approved to experimental, the updated package is available (amd64 only) from my home directory on gluck.

Suppose you have a master-master replication setup, and you know one of the tables has the wrong data. How do you re-sync it with the other server?

Warning: don’t just use any tool for this job! You may destroy your good copy of the data.

If your table is large, you’ll probably want to use a tool that can smartly find the differences in a very large dataset, and fix only the rows that need to be fixed. There are several tools that are either able to do this, or claim to be able to do this. However, most of them are not replication-aware, and are likely to either break replication or destroy data.

To see why this is, let’s look at a typical scenario. You have server1 and server2 set up as co-masters. On server1, your copy of sakila.film has correct data. On server2, somehow you are missing a row in that table. A hypothetical sync tool will compare the two copies of the data and find …

Debugging an existing application can be hard to bootstrap. Sometimes it just helps to observe the queries a web application is sending to the database. Unfortunately, the MySQL Query log does not directly tell the user which query goes to which database.
Continue reading "Observing the MySQL Query Log"

FedEx rang on my door today, delivering a large cardboard box. The Sender? Sun Microsystems, my new employer!

Upon opening it, I discovered the following:

Continue reading "A nice welcome package from Sun arrived today"

It's been close to 4 months since we released Cool Stack 1.2, so it's time to start thinking about the next release. Here's what we have planned so far and as always I'm looking for feedback from current and future users on what you'd like to see. Needless to say, that all currently known bugs will be fixed and the current patches will be rolled into the release. However, if you don't tell us about the problems you've run into, we won't be able to fix them. So, once again I'd like to encourage people to please post your problem/issue/tips etc. on the forum.

Here's a list of stuff we're currently looking at for Cool Stack 1.3 :

It's been close to 4 months since we released Cool Stack 1.2, so it's time to start thinking about the next release. Here's what we have planned so far and as always I'm looking for feedback from current and future users on what you'd like to see. Needless to say, that all currently known bugs will be fixed and the current patches will be rolled into the release. However, if you don't tell us about the problems you've run into, we won't be able to fix them. So, once again I'd like to encourage people to please post your problem/issue/tips etc. on the forum.

Here's a list of stuff we're currently looking at for Cool Stack 1.3 :

MySQL DBA Certification candidates need to know about a little known but important function.

PROCEDURE ANALYSE() is a rarely used function in these days of inexpensive disks. It is mainly used to suggest optimal column sizes. Forty years ago you needed to worry how to properly encode data so that it would fit on an eighty column punch card. Thirty years ago when hard disks were the size of stove or dishwasher, there was a need to conserve as much space as possible. Today people carry gigs of data in their pocket and a terabyte of disk is available at local stores next to other consumer products. So you can be less than optimal in your storage of data for the most part. There are exceptions. Remember that a smaller width index is going to be a faster index.

Let us pretend that we need to create a table to track item numbers and our data architect, boss, or SWAG tells us there will only be twenty item numbers, ranging from …

Its interesting when you look at MySQL database environments. Extremely popular in the MySQL world is to use commodity hardware and implement the LAMP stack.  Smaller projects and startup companies love this environment.  A simple example, a company needs to set up a web application, they buy some commodity hardware, set up replication and scale horizontally.  Everybody loves this and it works

It is a challenge for new MySQL DBAs to learn best practices for managing database servers. There are no books that teach you everything you need to know.  Key knowledge areas new MySQL DBAs need to learn: Best practices for installation and configuration.How to monitor and manage a database.How to monitor for tuning.Best practices for backup/recovery.Best security practices.What audit controls