On Thu, Dec 31, 2009 at 7:45 PM, Kevin Grittner <kevin.gritt...@wicourts.gov> wrote: > Robert Haas wrote: > >> What predicate locking? If you take ACCESS EXCLUSIVE locks on every >> read, that should serialize all access to every table. Predicate >> locking wouldn't do anything, because the table would be completely >> inaccessible to all competing transactions. > > Yeah, that's the benefit of starting with the ACCESS EXCLUSIVE locks, > but once I've confirmed that I've found all the places to get the > table level locks, the next step is to turn them into table level > SIREAD locks, and then to implement the SSI. Locking against > referenced objects is the only practical technique for implementing > predicate locking for production environments that I've seen. > > The phase where I'm making each referenced table totally inaccessible > to all competing transaction should be pretty short-lived. It just > gives me an interim milestone to test that piece in isolation before > going on to use it; which is great, but not a place to stop for long. > > Or have I totally misunderstood your suggestion?
Nope, you're on target. Although - if I were you - I would post the ACCESS EXCLUSIVE lock version of the patch for feedback. I can't speak for anyone else, but I'll read it. (Just clearly label it as what it is, of course.) ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
