On Tue, 6 May 2008, Tom Lane wrote:
If a misestimate of this kind is bugging you enough that you're willing
to change the query, I think you can fix it like this:
select ... from foo order by x limit n;
=>
select ... from (select ... from foo order by x) ss limit n;
The subselect will be planned without awareness of the LIMIT, so you
should get a plan using a sort rather than one that bets on the LIMIT
being reached quickly.
Surely if that's the case, that in itself is a bug? Apart from being
"useful", I mean.
Matthew
--
"Television is a medium because it is neither rare nor well done."
-- Fred Friendly
