Peter Geoghegan wrote: > > Your patch brings us one step closer to that goal. (The book says > > that this approach is good far sparse bitsets, but your comment says > > that we expect something near 50%. That's irrelevant anyway since a > > future centralised popcount() implementation would do this in > > word-sized chunks with a hardware instruction or branch-free-per-word > > lookups in a table and not care at all about sparseness.) > > I own a copy of Hacker's Delight (well, uh, Daniel Farina lent me his > copy about 2 years ago!). pop()/popcount() does seem like a clever > algorithm, that we should probably think about adopting in some cases, > but I should point at that the current caller to my > bloom_prop_bits_set() function is an elog() DEBUG1 call. This is not > at all performance critical.
Eh, if you want to optimize it for the case where debug output is not enabled, make sure to use ereport() not elog(). ereport() short-circuits evaluation of arguments, whereas elog() does not. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
