Re: Does IMMUTABLE property propagate?

From: Louis-David Mitterrand <vindex+lists-pgsql-sql(at)apartia(dot)org>
To: pgsql-sql(at)postgresql(dot)org
Subject: Re: Does IMMUTABLE property propagate?
Date: 2010-03-25 06:16:17
Message-ID: 20100325061616.GA4629@apartia.fr
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On Sat, Mar 06, 2010 at 04:31:55PM -0500, Tom Lane wrote:
> Petru Ghita <petrutz(at)venaver(dot)info> writes:
> > "..immediately replaced with the function value" doesn't mean that the
> > results of a previously evaluated function for the same parameters are
> > stored and reused?
>
> No, it means what it says: the function is executed once and replaced
> with a constant representing the result value.

So for example a function like:

CREATE OR REPLACE FUNCTION shorten_cruise_type(intext text) RETURNS text
AS $$
declare
outtext text;
begin
outtext = trim(regexp_replace(intext, E'\\s*Short( Break)?', '', 'i'));
return outtext;
end;
$$
LANGUAGE plpgsql;

could/should be declared immutable?

Thanks,

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