Wednesday, July 13 2011
PostgreSQL, skytools, Conferences

Back From CHAR(11)

CHAR(11) finished somewhen in the night leading to today, if you consider the social events to be part of it, which I definitely do. This conference has been a very good one, both on the organisation side of things and of course for its content.

It began with a perspective about the evolution of replication solutions, by Jan Wieck himself. In some way Skytools is an evolution of Slony, in the sense that it reuses the same concepts, a part of the design, and even share bits of the implementation (like the txid_snapshot datatype that were added in PostgreSQL 8.3). The evolution occured in choosing a subset of the features of Slony and then simplifying the user interface as much as possible. And with Skytools 3.0, those features that were removed but still are useful to solve real-life problems are now available too.

Of course the talk did approach the other replication solutions (not just the trigger based ones), and did compare RServ to Bucardo for example. And then all those were compared to the PostgreSQL core replication facilities, which are quite a different animal. It was a really nice keynote here, preparing the audience minds to make the most out of all the other talks.

I will not review all the talks in details, as I'm pretty sure some other attendees will turn into reporters themselves: scaling the write load!

Still repmgr got its share of attention. Greg Smith and Cédric Villemain did present both how to do read scaling and auto failover management with this tool, going into fine details about how it works internally and how to best design your services architecture for maximum data availibility. The question and answers section led to insist on the fact that you can not have data availibility with less than 3 production nodes.

Magnus Hagander detailed how flexible the core protocol support for replication (and streaming) really is. That flexibility means that you can quite easily talk this protocol from any application, and the idea of a wal proxy did pop out again (see Back from PgCon2010 article for my first mentionning of the idea). The main difference is that we now have synchronous replication support, so that the proxy could be trusted both for archiving and serving standbys.

Of course Simon still has lots of ideas about next 10 years of replication oriented projects for core PostgreSQL code, and his talk nicely summarized the previous 7 years. Future is bright, and guess what, it's beginning today!

We also heard about Heroku, and these guys are doing crazy impressive things. Like running 150 000 PostgreSQL instances, for example, showing that you can actually use our prefered database server in the hosting business. I expect that the maturing solution and tool sets providing data availibility are soon to be a game changer here. What they are doing is designing a flexible data architecture with strong guarantees ( no data loss). The cloud elasticity is reaching out from the stateless services, and those guys are making it happen now.

May you live in interresting times!