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Hi,
Le 9 oct. 08 à 21:30, Tom Lane a écrit :
There's not a lot you can do about that at the moment. 8.4 will have
the ability to inline functions returning sets, if they're SQL-
language
and consist of just a single SELECT, but existing releases won't do
it.
I'm actually using 8.3 functions cost/rows planner estimation to trick
it into avoiding nestloop into some INNER JOIN situations where any
amount of up-to-date statistics won't help.
Will the 8.4 ability to inline plain SQL still consider the given
hardcoded ROWS estimation?
FWIW the difference of timing of one of the queries where I'm using
this trick is about 35 mins or more against 48 seconds. It allows the
planner to choose MergeJoin paths instead of Nestloop ones, where
inner loop has several millions records, and definitely not just
several records, like planner/stats bet.
Regards,
- --
dim
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