Friday, December 11, 2009

Galera Author Interviewed by Himself

We just made a major software release, but I still don't see journalists queuing outside our office. Looks like I have to do the hard work and interview myself. In the following, I'll give rough reporter treatment to me:

So, what are we talking about?
MySQL/Galera release 0.7 - synchronous multi-master clustering solution for InnoDB.

Downloads? Where?
.e.g. here:

Sure, here:
But, can't you ask any longer questions?

Oh, sorry, assumed that you geek people prefer not to talk with natural language. But, what is this Galera thingie good for? For whom would you suggest this release?
Practically any innodb user can potentially benefit of MySQL/Galera. There are no unnecessary tweaks in the MySQL behavior. Odds are good that your application will notice no difference when compared with vanilla MySQL.

If high availability is your need, Galera provides that out of the box, due to synchronous replication. After committing, the data is safe in every active cluster node, simple as that.

And, if more performance is needed, Galera can boost your data access considerably. Note that, Galera scales even write intensive workloads. However, hot spots are poison for this replication method. If workload contains focused hot spots, the number of write-accepting masters should be reduced.

Is it good for production, anything to worry about?
We have tested this during a focused test session after 0.7pre release, and we are quite happy with the stability. Two issues were postponed for future maintenance release. There is obvious issue when running DDL and DML concurrently in the cluster. That should be avoided, if it ever were in your plans.

But no matter how much we can test in laboratory, for production use, it is anyway essential to evaluate with the real application and with test load that closely simulates production use.

How stable is it, can I go in engine room and pull out cables wildly?
yes! 0.7 release was designed to be fault tolerant and can recover from most of the expected and un-expected situations. It tolerates even ad-hoc engine room visits.

Does it support innodb plugin?
This build is over MySQL 5.1.39 and innodb plugin is in there. We have enabled innodb plugin in the build and did also some compatibility tests with it. No issues surfaced, but our testing was quite minimal. .e.g. no performance testing has been run with plugin version.
MySQL/Galera will start by default with builtin innobase engine.There is configuration sample in the distribution showing how innodb plugin can be loaded, if you want to play with it.

Everybody is talking of this emerging MariaDB, any plans on supporting that?
Yes, plans and even actions. MariaDB version will be available here:

Everybody is talking of PostgreSQL, any plans on supporting that?
PostgreSQL has been in our roadmap from the very beginning. However, reality bites, and in practice MySQL development has eaten all our resources so far. We plan to get PostgreSQL development rolling in near future, but it sure would help if some experienced PostgeSQL partner would join in this development.

Is this a cry for help, or what?

So, what's next?
Next in schedule is maintenance release 0.7.1, ETA before end of the year. It will mostly address issues in running DDL and DML concurrently. In general, the maintenance release cycle will be kept as short as possible.
Next major release will be 0.8, which has features for considerably faster node join operation. (currently we are limited by mysqldump speed...).
Also MariaDB porting will continue with added effort. One more cup of coffee, and I will promise MariaDB port during December time frame.

Thanks! What are we?
You are welcome

And what was it?
It was a pleasure