Re: Issue for partitioning with extra check constriants - Mailing list pgsql-performance

From Tom Lane
Subject Re: Issue for partitioning with extra check constriants
Date
Msg-id 1548.1285977377@sss.pgh.pa.us
Whole thread Raw
In response to Issue for partitioning with extra check constriants  (Josh Berkus <josh@agliodbs.com>)
Responses Re: Issue for partitioning with extra check constriants  (Josh Berkus <josh@agliodbs.com>)
List pgsql-performance
Josh Berkus <josh@agliodbs.com> writes:
> The issue is this: when a partitioned table is evaluated by the planner
> for constraint exclusion, it evaluates ALL check constraints on each
> partition, regardless of whether or not they include a referenced column
> in the query (and whether or not they relate to partitioning).

[ shrug ... ]  We do not promise that the current partitioning scheme
scales to the number of partitions where this is likely to be an
interesting concern.

*After* we have a real partitioning scheme, it might be worth worrying
about this sort of problem, if it's still a problem then.

> Are we talking "moderate", "hard" or "nearly impossible"?

We're talking "wasted effort on a dead-end situation".  The time that
would go into this would be much better spent on real partitioning.

            regards, tom lane

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