On Thu, Sep 23, 2004 at 08:29:25AM -0700, Mr Pink wrote: > Not knowing anything about the internals of pg, I don't know how this relates, but > in theory, > query plan caching is not just about saving time re-planning queries, it's about > scalability. > Optimizing queries requires shared locks on the database metadata, which, as I > understand it > causes contention and serialization, which kills scalability.
One of the guru's can correct me if I'm wrong here, but AFAIK metadata lookups use essentially the same access methods as normal queries. This means MVCC is used and no locking is required. Even if locks were required, they would be shared read locks which wouldn't block each other. -- Jim C. Nasby, Database Consultant [EMAIL PROTECTED] Give your computer some brain candy! www.distributed.net Team #1828 Windows: "Where do you want to go today?" Linux: "Where do you want to go tomorrow?" FreeBSD: "Are you guys coming, or what?" ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend
