Tom Lane wrote:
A bad estimate for physical-position correlation has only limited impact,
Ah! This seems very true with 8.3 but much less true with 8.0. On a legacy 8.0 system I have a hard time avoiding cases where a query like "select * from addresses where add_state_or_province = 'CA';" does a 2-second full-table scan instead of a 300ms index scan thanks to a poor physical order guess. I just sucked the table into 8.3 and am pleased to say that it picks a 200ms bitmap scan even with the misleading correlation. Thanks for bitmap scans guys! I'll shut up about this physical ordering stuff now and try to do better upgrading before posting. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
