When doing performance analyzes you often would want to see 95 percentile, 99 percentile and similar values. The "average" is the evil of performance optimization and often as helpful as "average patient temperature in the hospital".

Lets set you have 10000 page views or queries and have average response time of 1 second. What does it mean ? Really nothing - may be one page view was 10000 seconds and the rest was in low milliseconds or may be you had every single page view taking 1 second, which are completely different.

You also do not really care about average performance - the goal of good user experience is majority of users to have good experience and average is not a good fit here. Defining your response time goal in 95 or 99 percentile is much better. Say you say 99 percentile response time should be one second, this means only 1 percent of queries/page views are allowed to take more than that. For larger systems defining …

MySQL 5.1 is now released as "GA".

In this blog I will try to describe my opinions about this release and also try to set the expectations right for anyone trying out MySQL 5.1 GA.

What should you then expect from MySQL 5.1?

• If you are using MySQL 5.1 just as a 'better' version of MySQL 5.0 and you don't plan to use any of the new features in MySQL 5.1 then you are probably fine to try out MySQL 5.1. You should however not put it into production without testing it fully, preferably by running it on a couple of slaves for some weeks. It may even be the best to wait for a couple of minor/patch releases before putting the MySQL 5.1 server into production.
• Don't expect …

 
As you probably already know, yesterday the GA version of MySQL™ 5.1 has been released :)

To celebrate this great event, I have organized a little event with some of my friends @ Trieste University, Italy.

Since I am a physics alumn and I still have some friends who study physics, I decided to organize a sort of unofficial “Trieste MySQL™ 5.1 GA Day” to have some funny moments with them at the Physics Department ;)

I am using MySQL™ 5.1 since the third public version (5.1.5-beta, January 2006) and I have installed and tested all the 24 versions from 5.1.5-beta :)

For the occasion, I bought a chocolate pie and a good Italian sweet wine ( …

Working with number of hosting providers I always wonder how do they manage to keep things up given MySQL gives you so little ways to really restrict how much resources single user can consume. I have written over a year ago about 10+ ways to crash or overload MySQL and since that people have come to me and suggested more ways to do the same.

This is huge hole in MySQL design, thinking little about users isolations and resource quotas and interesting enough I have not seen significant changes in fresh our MySQL 5.1 GA or even something major on the roadmap for future MySQL versions. May be Drizzle will give it a thought ? This surely would help adoption by (especially low end) Hosting Providers and remember this exactly where a lot of kids start to develop their first sites and play with web technologies.

So how do the …

Sometimes MySQL is too helpful. Recently I was helping a very large man working on a very small laptop that had an overly sensitive mouse. Trying to scroll back and forth to examine the system variables with the mysql command-line client was very painful. It reminded me of the Atlantic Bottlenose Dolphin named Kai at the Texas State Aquarium pictured here that was too helpful when I tried to get him to splash 'just a little' for a picture. In this case the server was returning too much to see and the very large man in frustration handed his computer to me.


mysql> pager more
PAGER set to 'more'


I returned the laptop and the very large man could now control the scrolling. After a few moments we found what we were looking for.

'So how do I turn …

MySQL 5.1 is GA. Yay!

A lot of new features have been added, and the numbering convention of just adding a .1 doesn't really explain that. If I had of numbered it, I probably would have called it "6.0".

In some ways MySQL has done both themselves (and DBAs) a small injustice. While working at MySQL I met a lot of customers that tended to be conservative - they don't install first releases, but instead wait for the second release[1].

In the case of 5.1, just be aware that there will be quite a few more features, and with it will be more bugs. I think it's more stable than 5.0 - but you will still need to do plenty of testing.

I'm happy to see it finally released though - 3 years in the making!

But again if I had it my way, it would have been good to see a real "Point 1" release to 5.0. There were a lot of new features introduced in late 2005 that only required small …

MySQL 5.1 is GA. Yay!

A lot of new features have been added, and the numbering convention of just adding a .1 doesn't really explain that. If I had of numbered it, I probably would have called it "6.0".

In some ways MySQL has done both themselves (and DBAs) a small injustice. While working at MySQL I met a lot of customers that tended to be conservative - they don't install first releases, but instead wait for the second release[1].

In the case of 5.1, just be aware that there will be quite a few more features, and with it will be more bugs. I think it's more stable than 5.0 - but you will still need to do plenty of testing.

I'm happy to see it finally released though - 3 years in the making!

But again if I had it my way, it would have been good to see a real "Point 1" release to 5.0. There were a lot of new features introduced in late 2005 that only required small …

It’s time for another exciting installment of Log Buffer, the weekly review of database blogs.

On Prestidigitation of Oracle, Bradd Piontek gets it started with the second in a series on migration to 10g—Making the database a safer place, reviewing security-related changes in 10gR2. (Full disclosure: I should also mention that Bradd is now sitting just a few desks away from me.)

The ORACLE-BASE Blog has a dynamic duo of articles—one each on installing Oracle 11.1 and installing Fedora …

The GA announcement of MySQL 5.1 is getting closer by the minute! So it’s time for Position 3 in the MySQL 5.1 Use Case Competition.

3. Corrado Pandiani (Football Club Internazionale Milano Spa, Milan, Italy): Using Partitioning and Event Scheduler for online logging & real-time stats. See Corrado’s DevZone article, and his blog.

Thanks and congratulations, Corrado! I hope you are in a position to take advantage of your free MySQL Conference & Expo 2009 Pass, including a dinner with MySQL co-founder …

Follow the link: MySQL 5.1 Use Case Competion

… California dreamin’