Re: CHECK constraints and optimizations - Mailing list pgsql-general

From Tom Lane
Subject Re: CHECK constraints and optimizations
Date
Msg-id 26714.1083891741@sss.pgh.pa.us
Whole thread Raw
In response to Re: CHECK constraints and optimizations  (Martijn van Oosterhout <kleptog@svana.org>)
Responses Re: CHECK constraints and optimizations  (Martijn van Oosterhout <kleptog@svana.org>)
List pgsql-general
Martijn van Oosterhout <kleptog@svana.org> writes:
> I can't see why this wouldn't work.

Doubtless you could do it.  The problem with the idea is that those
inference tests are pretty expensive.  I think that any such thing would
waste significant numbers of cycles on ordinary queries while only being
a win on a few poorly-written queries.

We do have to make a tradeoff between planning time and execution time,
and I fear that this idea is not going to be a win in those terms.
If you feel like experimenting, though, go for it ...

            regards, tom lane

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