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Re: One-time plans

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Simon Riggs" <simon(at)2ndquadrant(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: One-time plans
Date: 2007-04-02 16:20:35
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Lists: pgsql-hackers
"Simon Riggs" <simon(at)2ndquadrant(dot)com> writes:
> ISTM we've just invented the concept of one-time plans to allow CREATE
> INDEX to work effectively with HOT.

> I'd like to extend that thought back over towards constraint exclusion.
> Currently we don't allow STABLE functions to be used for constraint
> exclusion because that mean plans were valid only if they are
> immediately executed.

> It seems like a very small act to force the plan to be one-time only
> when we have successfully used a STABLE function to exclude a table.

No.  STABLE functions are not stable enough for that --- you'd have to
assume they are unchanging across the whole transaction.

			regards, tom lane

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