Folks,
I've noticed that queries of the form
SELECT DISTNCT foo, bar, baz
FROM quux
WHERE ...
perform significantly worse than the equivalent using GROUP BY.
SELECT foo, bar, baz
FROM quux
WHERE ...
GROUP BY foo, bar, baz
Where would I start looking in order to make them actually equivalent
from the planner's point of view? Also, would back-patching this make
sense? It doesn't change any APIs, but it does make some queries go
faster.
Cheers,
David.
--
David Fetter <david@[EMAIL PROTECTED]
> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david.fetter@[EMAIL PROTECTED]
to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate
--
Sent via pgsql-hackers mailing list (pgsql-hackers@[EMAIL PROTECTED]
)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
|
