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Old 04-09-2008, 09:19 AM
Tom Lane
 
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Default Re: Query runs fast or slow

felix-accts-pgsql@crowfix.com writes:
> EXPLAIN ANALYZE doesn't show the slow timing
> because it requires values, not $n placeholders,


To analyze the plan used for a parameterized query, try

PREPARE foo(...) AS SELECT ... $n ...

EXPLAIN ANALYZE EXECUTE foo(...)

But I already know what you're going to find: the planner's estimates
for the range query are not going to be very good when it has no idea
what the range bounds are. This is a situation where it may be best
to absorb the hit of re-planning each time instead of using a generic
parameterized plan.

regards, tom lane

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