On Thu, Nov 28, 2013 at 2:23 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Thu, Nov 28, 2013 at 1:46 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>> We could add an extra test in FastPathGrantRelationLock's loop to make >>> it remember the first unused slot rather than the last one, but that >>> would add some cycles there, partially negating any benefit. Instead >>> I propose that we reverse the direction of the search loop, as attached. > >> Well, the reason why the array is only 64 bytes in size is to make >> sure that searching the whole thing is really fast. We figure we're >> going to have to do that often, so it needs to be cheap. If it's not, >> we're hosed already, I think. > > I actually suspect the bitmask manipulations cost more than the touches > of fpRelId[]. I agree that there's no reason to think that this area > needs really tense micro-optimization, but if we can get some savings for > zero added cost/complexity, why not?
Sure. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
