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Re: WIP: default values for function parameters

From: Peter Eisentraut <peter_e(at)gmx(dot)net>
To: pgsql-hackers(at)postgresql(dot)org
Cc: "Pavel Stehule" <pavel(dot)stehule(at)gmail(dot)com>, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: WIP: default values for function parameters
Date: 2008-11-30 15:48:42
Message-ID: 200811301748.43645.peter_e@gmx.net (view raw or flat)
Thread:
Lists: pgsql-hackers
On Thursday 27 November 2008 00:14:19 Pavel Stehule wrote:
> I am sending actualized versions - I accepted Tom's comments - default
> expressions are serialised List stored in text field.

OK, this is looking pretty good.

There is a structural problem that we need to address.  With your patch, 
pg_dump produces something like this:

CREATE FUNCTION foo(a integer = 1, b integer = 2, c integer = 3) RETURNS 
integer
    LANGUAGE sql
    AS $_$ SELECT $1 + $2 + $3; $_$;

ALTER FUNCTION public.foo(a integer = 1, b integer = 2, c integer = 3) OWNER 
TO peter;


The second command is rejected because default values are only accepted in 
CREATE FUNCTION.

There are two ways to fix this, both having some validity:

1. We create a second version of pg_get_function_arguments() that produces 
arguments without default values decoration.  This is probably the 
technically sound thing to do.

2. We accept the default values specification and ignore it silently.  Note 
that we already silently ignore the argument names.  ALTER FUNCTION foo(a 
int, b int) will also act on a function defined as foo(x int, y int).

Comments?

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Next:From: Pavel StehuleDate: 2008-11-30 16:09:28
Subject: Re: WIP: default values for function parameters
Previous:From: Tom LaneDate: 2008-11-29 21:06:54
Subject: Re: BUG #4553: HOLD cursors not materializing results fully

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