When I set-up a MySQL HA environment for customers I usually do some final fail over tests after configuring the whole beast.

To check if the application behaves like expected I always run my little test application (test.sh) from the server(s) where the customers application runs. It displays "graphically" how the application behaves and you can show to the customer immediately what is going on...

Make sure, that you point it to the VIP (virtual IP) or the LB (load balancer).

It was really useful for me and I recommend you to do your HA fail over tests also at least with this little tool to avoid evil surprises in the future.

MySQL University has been running for the last 18 months, and we’ve covered a wide range of topics, from the internals of MySQL right up to Amazon’s EC2, using MySQL in the Solaris/OpenSolaris Webstack and a description of the forthcoming MySQL Online Backup.

Personally, I think they’re great. Obviously many times I am scribe and am there for the sessions, but I listen to lots of the sessions anyway, and I’m yet to be disappointed by the content. What’s really great is that in all the cases the person you are listening to is probably the person that either developed, or helped drive development of the particular function, or, in the case of some of the external tools (EC2, for example), these guys are expert in it. The experience is not quite as thrilling as attending the MySQL User Conference, but the content is just the same.

The problem is that …

It’s been a while since my last post! I have a few half-written entries, but I figured I just get one out there so I don’t appear to have dropped off the face of the planet

Being more of a DBA than a sysadmin myself, I’ve noticed that there is a surprising dearth of information regarding how to actually get nagios set up to monitor MySQL, especially if you’re not experienced with nagios.

In my own experience, MySQL monitoring often ends up being a homegrown thing, especially if you’re a small shop. It is definitely a good idea to consolidate all of your monitoring, DB-related or not, into one solution: roll-your-own monitoring solutions can be brittle and burn you in the end. One example that comes to mind, a few years back i had a quick perl-based script to monitor replication and set it to mail a few people based on some threshold. Took me 1 hour to write and worked well enough, except, six months later, when some …

So Yves knowing my affinity for all things solid state forwarded me this link, http://torvalds-family.blogspot.com/2008/10/so-i-got-one-of-new-intel-ssds.html , it seems Linus Torvalds picked up one of the new Intel SSD drives ( if anyone wants to send me one to test that would be cool ).  Whats interesting is he says the thing just rocks.  But how will this perfom in a database environment?  Not 100% sure, but I think it’s going to perform worse then the mtron or memoright drvies I have tested.  Why?  Well the drive is MLC not SLC.  Anandtech has a great review the Intel SSD, with an awesome explination with accompaning benchmarks on SLC -vs- MLC.  Most of these tests are performed in a windows environment, and I …

The trouble with slave lag is that you often can't see it coming. Especially if the slave's load is pretty uniform, a slave that's at 90% of its capacity to keep up with the master can be indistinguishable from one that's at 5% of its capacity.

So how can you tell when your slave is nearing its capacity to keep up with the master? Here are three ways:

One: watch for spikes of lag. If you have Cacti (and these Cacti templates for MySQL) you can see this in the graphs. If the graphs start to get a little bumpy, you can assume that the iceberg is floating higher and higher in the water, so to speak. (Hopefully that's not too strange a metaphor.) As the slave's routine work gets closer and closer to its capacity, you'll see these spikes get bigger and "wider". The front-side of the spike will always be less than a 45-degree angle in ordinary operation[1] but …

Do you have a master-slave MySQL set up?  Ever do DDL changes on the master?  You may be hit with a serious data integrity bug.  Read on. One of our clients does a regular rename tables on the master to keep the current table small and archive off old data.  We’d occasionally be hit by [...]

In many programing languages it is possible to shorten if statements using what’s called the ternary operator. It is sometimes referred as the “one line if statement” or the “short if statement”. This can help at times to produce cleaner code, however use this operator wisely as it is not always best to be used for more complicated statements.

PHP Example of an if statement

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if($nFoo > 0)
{
   echo "I'm at the work.";
}
else
{
   echo "I'm at home.";
}

PHP Example using the ternary operator

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      echo $nFoo > 0 ? "I'm at the work." : "I'm at home.";

The expression (expr1) ? (expr2) : (expr3) evaluates to expr2 if expr1 evaluates to …

What do football allegiances have to do with choosing between Oracle and MySQL? READ MORE

“So, I suppose MySQL’s main competitor is Oracle?” is a frequent question I get asked by the press. “Well, we don’t really compete heads-on with other databases. We co-exist! Just as an example: Over a third of respondents in an Oracle User Group survey said they also use MySQL”, I answer.

The reporter then continues “But everyone has a main competitor. Don’t you plan for people to migrate from Oracle to MySQL?”. I continue with “Not really. Migrations do happen, but not all that often. MySQL tends to be used in new applications.”

“But surely you must have some competitive atmosphere, or equivalent feelings towards Oracle.” The reporter never gives up. “Don’t you at least internally joke about your relationship with Oracle?”.

And that’s where I will now have a new answer for whichever reporter nexts goes …

We released Cool Stack 1.3.1 recently. This was the last release that was built to work on releases as old as Solaris 10 01/06 (Update 1). Going forward, future versions of the stack will only be supported on newer Solaris 10 updates. So I'd like to urge everyone who is running older releases to please schedule their systems for upgrade. We highly recommend that you upgrade to at least Solaris 10 01/08 (Update 5) as it has many performance, security and other fixes.

For some time now, we've had two different stacks for Solaris 10 and OpenSolaris - Cool Stack for Solaris 10 and Web Stack for OpenSolaris. We cannot continue to sustain this model  where we have two different source bases with slightly different …