On Fri, Dec 4, 2015 at 2:44 PM, Jim Nasby <jim.na...@bluetreble.com> wrote: > I suspect Cachegrind[1] would answer a lot of these questions (though I've > never actually used it). I can't get postgres to run under valgrind on my > laptop, but maybe someone that's been successful at valgrind can try > cachegrind (It's just another mode of valgrind).
I've used Cachegrind, and think it's pretty good. You still need a test case that exercises what you're interested in, though. Distributed costs are really hard to quantify. Sometimes that's because they don't exist, and sometimes it's because they can only be quantified as part of a value judgement. As frustrated as I've sometimes been with those discussions, I do recognize that there has to be a middle ground, and that the emphasis on distributed costs has as much to do with fairness for every contributor as anything else. I would have appreciated some attempt to have quantified the overhead here, but would not have insisted on Robert being as thorough as he conceivably could have been. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
