"Harry Hehl" <Harry.Hehl@xxxxxxxxxxxxxx> writes: > Why does vacuum full and reindex make a difference if the 3 tables are > never updated or records deleted? Probably because you did an ANALYZE somewhere and updated the planner's stats. I think your major problem is poor estimation of the ds_tables result: > -> Seq Scan on ds_tables (cost=0.00..59.80 rows=1 > width=48) (actual time=15.208..15.968 rows=121 loops=1) > Filter: ((lower(name) <> 'ds_omdatatest'::text) AND > (lower(name) <> 'ds_ommessage'::text) AND (lower(name) <> > 'ds_omusersetting'::text) AND (lower(name) <> 'ds_omloginsession'::text) > AND (lower(name) <> 'ds_omclassdef'::text) AND (lower(name) <> > 'ds_omuser'::text) AND (lower(name) <> 'ds_omusergroupsetting'::text) > AND (lower(name) <> 'ds_omtestobject'::text) AND (lower(name) <> > 'ds_omhomedirectory'::text) AND (lower(name) ~~ 'ds_om%'::text)) If you have an index on lower(name) then ANALYZE will collect statistics on it, and you'd get an estimate of the result size that was better than random chance ... but I bet you have no such index. You might get some improvement from raising the default statistics target, too. regards, tom lane
