On Sat, Mar 24, 2012 at 3:22 PM, Joshua Berkus <j...@agliodbs.com> wrote:
> Billy, > > > I've done a brief search of the postgresql mail archives, and I've > > noticed a few projects for adding query caches to postgresql, (for > > example, Masanori Yamazaki's query cache proposal for GSOC 2011), > > ... which was completed, btw. Take a look at the current release of > pgPool. > > Are you proposing this for GSOC2012, or is this just a general idea? > just a general idea, but if someone wants to work on it for GSOC2012, I wouldn't mind giving a helping hand. I'm not a student, so GSOC probably doesn't apply to me. > > > I'm wondering if anyone would be interested in a query cache as a > > backend to postgresql? I've been playing around with the postgresql > > code, and if I'm understanding the code, I believe this is possible. > > Well, you'd have to start by demonstrating the benefit of it. The > advantage of query caches in proxies and clients is well-known, because you > can offload some of the work of the database onto other servers, this > increasing capacity. Adding a query cache to the database server would > require the "query identity recognition" of the cache to be far cheaper (as > in 10X cheaper) than planning and running the query, which seems unlikely > at best. > > I figured I'd create the md5 digest of the sourceText of a query, and then look that up in a hash. I don't think that will be very expensive. I'll have another hash to keep track of which queries are dependent on which relations, so that when a relation is changed somehow (and committed), the query is then invalidated and removed from the query hash. Billy
