Re: Constraint exclusion won't exclude parent table

>
>
> Yeah, it's not expected that that's going to cost much. I am suspicious
> that what you are looking at is mostly measurement overhead: during
> EXPLAIN ANALYZE, each plan node has to do two gettimeofday() calls per
> call, and there are lots of platforms where that is significant relative
> to the actual work done per node.
>
> You might try comparing the overall times for select count(*) from ...
> rather than EXPLAIN ANALYZE for these two cases. If those times are
> much closer together than what you're getting from EXPLAIN ANALYZE,
> then you've got a machine with expensive gettimeofday() and you have
> to take your measurements with an appropriate quantum of salt.
>
> regards, tom lane

Interesting..

Direct query:
Time: 374336.514 ms

Indirect query:
Time: 387114.059 ms

Mystery solved. Thanks again Tom.

For what it’s worth: Linux 3.2.0-4-amd64 Debian 3.2.46-1+deb7u1 x86_64
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