Blogit

As you might already know, DBT2 is an OLTP benchmark similar (but not equivalent) to venerable TPC-C. A couple of months ago I tried it with Galera on Amazon EC2 to see how Galera performed in a non-LAN environment. It did quite well, especially in high availability regard. Since then Galera saw a whole lot of bugfixes and improvements, so the time has come to try it once again. This time it will be 'large' AWS instances, almost 8 gigs of RAM and two CPU cores, you know, Big Iron or something.

How would Galera perform in this setup?

Hmm.., It is becoming obvious that I cannot figure out different topic lines anymore.

We have a list of features, that we are planning to add to Galera replication before publishing first release. Causal order, was one such requirement in our list and we had lengthy discussions of how to deal with this.

That's how my friend, Boss, would summarize our experiences with new parallel replication applying method, which is our latest enhancement in the Galera applying module.

...we wanted to find this out, and stressed Galera cluster heavily with sysbench oltp complex mode test. We ran the same test against plain MySQL 5.1.28rc and Galera clusters configured with 1-4 nodes. The results show that Galera scales steadily with this load and already 2 node Galera cluster was always faster than plain MySQL 5.1.28.rc.

sysbench

There has been a lot of engineering activity during recent weeks. That has kept me busy writing code and I totally slipped blogging effort. Writing code and blogging seem happen in different planets.

Anyway, here is a short summary of recent engineering activities:

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.

This is the first in the series of articles about Galera on Amazon EC2, here's the follow up.
Galera benchmarks on Amazon EC2 have been long overdue. There are at least 3 reasons why EC2 performance is so important to Galera project:

Don't worry if the title does not make much sense to you. RBR here refers to MySQL 5.1 Row Based Replication method, which we utilize in latest Galera release. Galera, on the other had, is also known as a multi "oar motored" rowing boat. That should explain the title semantics to you.

I got feedback from "the guys" that my benchmark figures are dull to read and we need fancy diagrams showing how Galera scales. So, I played with gnuplot to get something to begin with.

Galera development has finally reached state where it is possible to start serious testing with real DBMS benchmarks. However, current Galera release, supports only SQL statement level replication. The row data level (utilizing MySQL Row based Replication (RBR)), is under development still. But, even with statement level, the scalability seems considerably good and is worth testing.