rant

A short discussion with Baron at Henrik's blog has stirred my eloquence.

Baron points to a great post by Josh Berkus where Josh contemplates the database clustering issues from a novel viewpoint. The post is really insightful. But I'm going to top that (albeit not so skilfully).

So, when I posted new benchmarks about intercontinental synchronous replication performance, I kinda was not sure if that 6000 km disaster recovery scenario was not blown out of proportions.

So, the other day I posted the performance benchmarks for the multi-master MariaDB/Galera cluster. Spectacular performance. But some of you may justifiably say:

Dedicated to Fernando Pedone and other modest and courageous researchers whose work made this possible.

Sysbench Synchrones Transatlantiques

One of the pitch lines of the Drizzle project in their rewriting of MySQL code is to rely on standard libraries and make it a full blown C++ project, implying that there's no reason to hold back.

When we started Galera we explicitly decided to do it in C. We didn't have a confidence that libstdc++ was mature enough and expected to have all sorts of problems with it.

Bank restaurant that I have visited today and believe to be one of the largest restaurants (seat-wise) in Helsinki had elevated customer self-service to unparalleled (or rather super-paralleled) heights. The single mutex (cashiers) is locked only once and only to pay for food and grab fork and knife. The rest of IO (choosing and loading food) was totally asynchronous and evenly distributed between serving tables.

So we've been there.

In my opinion the conference was a great success. Our presentation was not, but that's another story. Percona really showed what conferencing is about. Don't know about MySQL. It was behind the closed doors. Valiant guardians strictly watched that you didn't overhear a word of Sacred Knowledge. Hell, even to get to the Expo hall you had to pay $25 (that's right, you had to pay for watching advertisement) and surrender information about your private life, like your phone number and how you learned about the Expo.

Today I have fixed an "optimization" which caused up to 10x performance degradation. In case you are interested, it was my optimization. And no, it was not iterating over 1000000-something long list. And it was not some hastily assembled patch. It was deliberately engineered optimization. I didn't even care to check how well it optimizes - so obviously neat it was.

If you're about to use the database cluster to scale performance of your application, you need some way to balance the load between the nodes. Ideally application should be smart enough to be able to distribute it's connections between different hosts and fail over. But in practice this is rarely the case.