Re: Update - Mailing list pgsql-sql

From Kyle
Subject Re: Update
Date
Msg-id 3AD71410.F2A1B252@actarg.com
Whole thread Raw
In response to Update  (Kyle <kyle@actarg.com>)
List pgsql-sql
Tom Lane wrote:

> Kyle <kyle@Actarg.com> writes:
> > It appears that the first function would get evaluated first under 7.0.3
> > but the last function gets evaluated first under 7.1.  Is that accurate?
>
> Actually, I was under the impression that (all else being equal) WHERE
> clauses would get evaluated right-to-left in 7.0.* as well.  I was
> meaning to figure out where the clause order reversal is happening and
> undo it, but didn't get around to it for 7.1.
>
> > Is there a way to control which functions are given precidence?
>
> Nope, not at the moment.  The code has remnants of a notion of cost of
> evaluation for functions, but it's not being used for anything ...
>

Might be interesting to have something like:

create function ... as ... with cost=x;

It would also be cool to supply a default set of parameters to the function.
Then "vaccum analyze" or some such thing could execute the functions, time
them, and store cost data internally...

create function ... as ... with default(3,7,4);
or
create function myfunc (int4 3, float8 7, numeric 4) ...;

BTW, great job on 7.1!  Kudos to all the developers who are working so hard
to make it happen.


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