Re: better support of out parameters in plperl

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: Pavel Stehule <pavel(dot)stehule(at)hotmail(dot)com>, pgsql-patches(at)postgresql(dot)org, david(at)fetter(dot)org
Subject: Re: better support of out parameters in plperl
Date: 2006-09-03 01:23:01
Message-ID: 44FA2E75.2000601@dunslane.net
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers pgsql-patches


I think it has to wait to 8.3. It's a complete mess that was submitted
unheralded at the last moment. Pavel needs to get into the habit of
submitting ideas first, not just patches. And there must be proper
documentation and working regression tests.

cheers

andrew

Bruce Momjian wrote:
> Uh, were are we in fixing/reviewing this?
>
> ---------------------------------------------------------------------------
>
> Andrew Dunstan wrote:
>
>> I wrote:
>>
>>> Pavel Stehule wrote:
>>>
>>>> Hello,
>>>>
>>>> I send two small patches. First does conversion from perl to
>>>> postgresql array in OUT parameters. Second patch allow hash form
>>>> output from procedures with one OUT argument.
>>>>
>>>>
>>> I will try to review these in the next 2 weeks unless someone beats me
>>> to it.
>>>
>>>
>>>
>> I have reviewed this lightly, as committed by Bruce, and have some
>> concerns. Unfortunately, the deathof my main workstation has cost me
>> much of the time I intended to use for a more thorough review, so there
>> may well be more issues than are outlined here.
>>
>> First, it is completely undocumented.
>>
>> Second, this comment is at best confusing:
>>
>> /* if value is ref on array do to pg string array conversion */
>>
>>
>> Third, it appears to assume that we will have names for all OUT params. But names are optional, as I understand it. Arguably, we should be treating the returns positionally, and thus return an arrayref when there are OYT params, not a hashref, and ignore the names - after all, all perl function args are nameless, in fact, even if you use a naming convention to refer to them.
>>
>> Fourth, I don't understand the change: "allow hash form output from procedures with one OUT argument." That seems very non-orthogonal, and I can't see any good reason for it.
>>
>> Lastly, if you look at the expected output as committed,it appears to have been prepared without being actually examined, for example:
>>
>>
>> CREATE OR REPLACE FUNCTION test05(OUT a varchar) AS $$
>> return {a=>'ahoj'};
>> $$ LANGUAGE plperl;
>> SELECT '05' AS i,a FROM test05();
>> i | a
>> ----+-----------------
>> 05 | HASH(0x8558f9c)
>> (1 row)
>>
>>
>> what???
>>
>> And now that I look I see every buildfarm box broken on PLCheck. That's no surprise at all.
>>
>>
>> The conversation regarding these features appears only to have started on July 28th, which was probably much too late given some of the issues. Unless we can solve these issues very fast I would be inclined to say this should be tabled for 8.3. I think this is a fairly good illustration of the danger of springing a feature, largely undiscussed, on the community just about freeze time.
>>
>> cheers
>>
>> andrew
>>
>
>

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Bruce Momjian 2006-09-03 01:27:07 Re: better support of out parameters in plperl
Previous Message Bruce Momjian 2006-09-03 01:16:21 Re: [COMMITTERS] pgsql: Change FETCH/MOVE to use int8.

Browse pgsql-patches by date

  From Date Subject
Next Message Bruce Momjian 2006-09-03 01:27:07 Re: better support of out parameters in plperl
Previous Message Bruce Momjian 2006-09-03 01:16:21 Re: [COMMITTERS] pgsql: Change FETCH/MOVE to use int8.