> Greets, > > I'm trying to figure out why the following SELECT has become slow > (hardware, > code changes, etc) and would appreciate any comments on interpreting the > EXPLAIN ANALYZE output. It *used* to take a few seconds at most, but not > anymore... In figuring out which part is taking so long, what's the > important > bit to examine (besides making sure indexes are being used)? Presumably > "actual time="? > > If I can identify which index is taking the longest from the output below, > then I can look at moving it to a faster TABLESPACE or something. > > > explain analyze > SELECT pl.sss, pl.did, pl.lid, pr.rank, plc.obl > FROM plink pl LEFT JOIN prank pr USING (did) > LEFT JOIN plink_count plc ON md5(plc.did)=md5(pr.did) > LEFT JOIN snames s ON s.name=pl.sss > WHERE > s.bsit=0 AND s.disabled=0 AND > s.prankignore=0 AND > pl.lid = lower(E'stuff'); >
See this http://explain.depesz.com/s/THh There's something very wrong with snames - the planner expects 22 rows but gets 164147851. Which probably causes a bad plan choice or something like that. Try to analyze the snames table (and maybe increase the statistics target on the columns). regards Tomas -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
