RelStorage: A New ZODB Storage

I’m writing RelStorage, a new storage implementation for ZODB / Zope / Plone. RelStorage replaces PGStorage. I’ve put up a RelStorage Wiki page and the zodb-dev mailing list has been discussing it. There is no stable release yet, but a stable release is planned for this month.

While performance is not the main goal (reliability and scalability are more important), I was pleasantly surprised to discover last week that creating a Plone 3 site in RelStorage on PostgreSQL 8.1 is a bit faster than doing the same thing in FileStorage, the default ZODB storage. Clearly, the PostgreSQL team is doing a great job!

Several years ago I put together an early prototype of PGStorage. I recall discovering that PostgreSQL was terribly slow at storing a lot of BLOBs. I read about the soon-to-come TOAST feature, but I wasn’t sure it would solve the problem, so I discarded the whole idea for years. Today, PostgreSQL seems to have no problem at all with this kind of work. It sure has come a long way.

RelStorage also connects to Oracle 10g. According to benchmarks, Oracle has a slight performance advantage, perhaps due to the “read only” isolation mode that Oracle provides. It might be useful for PostgreSQL to get that feature too.

I’m considering setting up a MySQL adapter for RelStorage as well. When the database is in MySQL and Zope is running in mod_wsgi, we could say that the “P” in LAMP stands for Plone!