[PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Yugo Nagata <nagata@sraoss.co.jp>

Дата:

28 декабря 2017 г. в 12:04:22

Hi,

Attached is a patch to implement a feature to get the current function
name by GET DIAGNOSTICS in PL/pgSQL function.

Currentyly, we can get call stack by GET DIAGNOSTICS PG_CONTEXT, but
we cannot get the function name directly. One of our clients wanted
this feature for debugging, and this was realized by creating a 
function that extracts the function name string from call stack. 
However, the overhead of function calls was not small, and it
caused performance regression. 

I found that there are other needs for this feature[1], so I have
implemented this.

[1] https://stackoverflow.com/questions/12611596/getting-name-of-the-current-function-inside-of-the-function-with-plpgsql

Example:

postgres=# CREATE FUNCTION test() RETURNS void 
LANGUAGE plpgsql AS $$
DECLARE t text;
BEGIN
GET DIAGNOSTICS t = FUNCTION_NAME;
RAISE INFO 'function name: %', t;
END;
$$;
CREATE FUNCTION

postgres=# select test();
INFO:  function name: test()
 test 
------
 
(1 row)

Regards,

-- 
Yugo Nagata

Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Tatsuo Ishii <ishii@sraoss.co.jp>

Дата:

31 декабря 2017 г. в 11:54:06

>> Attached is a patch to implement a feature to get the current function
>> name by GET DIAGNOSTICS in PL/pgSQL function.
> 
> Could you add it to the nexf CF, I have not seen it there? Maybe the
> deadline is tonight...

I have added this to the next CF.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp

Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Yugo Nagata <nagata@sraoss.co.jp>

Дата:

31 декабря 2017 г. в 13:32:19

On Sun, 31 Dec 2017 17:54:06 +0900 (JST)
Tatsuo Ishii  wrote:

> >> Attached is a patch to implement a feature to get the current function
> >> name by GET DIAGNOSTICS in PL/pgSQL function.
> > 
> > Could you add it to the nexf CF, I have not seen it there? Maybe the
> > deadline is tonight...
> 
> I have added this to the next CF.

Thank you.

> 
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp


-- 
Yugo Nagata

Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Yugo Nagata <nagata@sraoss.co.jp>

Дата:

11 января 2018 г. в 05:03:26

On Sun, 31 Dec 2017 11:57:02 -0500
Tom Lane  wrote:

> Yugo Nagata  writes:
> > Attached is a patch to implement a feature to get the current function
> > name by GET DIAGNOSTICS in PL/pgSQL function.
> 
> While this is certainly not a very large patch, it's still code that
> we'd have to maintain forever, so I think it's appropriate to ask
> some harder questions before accepting it.
> 
> 1. I'm having a hard time visualizing an actual concrete use case for
> this --- exactly when would a function not know its own name?  Neither
> your "our client wanted it" justification nor the cited stackoverflow
> question provide anything close to an adequate rationale.  I can think of
> concrete uses for an operation like "give me the name of my immediate
> caller", but that's not what this is.

Our client's use case was mainly to output debug messages at begining and
end of functions by using the same code. In addition, names of cursors
declared in the function were based on the function name, and they wanted
to get the function name to handle cursors.

However, I don't inisist on this patch, so If anyone other don't need this
feature, I'll withdraw this.

Regards,

> 
> 2. The specific semantics you've chosen --- in effect, regprocedureout
> results --- seem to be more because that was already available than
> anything else.  I can imagine wanting just the bare name, or the
> schema-qualified name, or even the numeric OID (if we're in the
> business of introspection, being able to look up the function's own
> pg_proc entry might be useful).  I'm not proposing that we offer
> all those variants, certainly, but without concrete use cases it's
> pretty hard to be sure we picked the most useful behavior.
> 
> 3. In connection with #2, I'm dubious that FUNCTION_NAME is le mot
> juste, because that would seem to imply that it is just the name,
> which it isn't.  If we stick with the regprocedureout semantics
> I'd be inclined to propose FUNCTION_SIGNATURE.
> 
> 			regards, tom lane
> 


-- 
Yugo Nagata

Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Andres Freund <andres@anarazel.de>

Дата:

2 марта 2018 г. в 01:29:58

Hi,

On 2018-01-11 11:03:26 +0900, Yugo Nagata wrote:
> However, I don't inisist on this patch, so If anyone other don't need this
> feature, I'll withdraw this.

Given this is where the discussion dried up more than a month ago I'm
inclined to mark this as rejected unless somebody wants to argue
otherwise?

Greetings,

Andres Freund

Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Yugo Nagata <nagata@sraoss.co.jp>

Дата:

6 марта 2018 г. в 06:09:31

On Thu, 1 Mar 2018 14:29:58 -0800
Andres Freund  wrote:

> Hi,
> 
> On 2018-01-11 11:03:26 +0900, Yugo Nagata wrote:
> > However, I don't inisist on this patch, so If anyone other don't need this
> > feature, I'll withdraw this.
> 
> Given this is where the discussion dried up more than a month ago I'm
> inclined to mark this as rejected unless somebody wants to argue
> otherwise?

I have no objection.

Thans,

> 
> Greetings,
> 
> Andres Freund


-- 
Yugo Nagata

Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Tom Lane <tgl@sss.pgh.pa.us>

Дата:

31 декабря 2017 г. в 19:57:02

Yugo Nagata  writes:
> Attached is a patch to implement a feature to get the current function
> name by GET DIAGNOSTICS in PL/pgSQL function.

While this is certainly not a very large patch, it's still code that
we'd have to maintain forever, so I think it's appropriate to ask
some harder questions before accepting it.

1. I'm having a hard time visualizing an actual concrete use case for
this --- exactly when would a function not know its own name?  Neither
your "our client wanted it" justification nor the cited stackoverflow
question provide anything close to an adequate rationale.  I can think of
concrete uses for an operation like "give me the name of my immediate
caller", but that's not what this is.

2. The specific semantics you've chosen --- in effect, regprocedureout
results --- seem to be more because that was already available than
anything else.  I can imagine wanting just the bare name, or the
schema-qualified name, or even the numeric OID (if we're in the
business of introspection, being able to look up the function's own
pg_proc entry might be useful).  I'm not proposing that we offer
all those variants, certainly, but without concrete use cases it's
pretty hard to be sure we picked the most useful behavior.

3. In connection with #2, I'm dubious that FUNCTION_NAME is le mot
juste, because that would seem to imply that it is just the name,
which it isn't.  If we stick with the regprocedureout semantics
I'd be inclined to propose FUNCTION_SIGNATURE.

			regards, tom lane

Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Fabien COELHO <coelho@cri.ensmp.fr>

Дата:

31 декабря 2017 г. в 11:07:27


> Attached is a patch to implement a feature to get the current function
> name by GET DIAGNOSTICS in PL/pgSQL function.

Could you add it to the nexf CF, I have not seen it there? Maybe the 
deadline is tonight...

-- 
Fabien.

Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Fabien COELHO <coelho@cri.ensmp.fr>

Дата:

31 декабря 2017 г. в 14:18:31



> Attached is a patch to implement a feature to get the current function 
> name by GET DIAGNOSTICS in PL/pgSQL function.

Shouldn't it be tested somewhere?

-- 
Fabien.

Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

Дата:

2 января 2018 г. в 21:25:44

On 12/31/17 11:57, Tom Lane wrote:
> 3. In connection with #2, I'm dubious that FUNCTION_NAME is le mot
> juste, because that would seem to imply that it is just the name,
> which it isn't.  If we stick with the regprocedureout semantics
> I'd be inclined to propose FUNCTION_SIGNATURE.

The SQL standard has diagnostics items ROUTINE_CATALOG, ROUTINE_SCHEMA,
ROUTINE_NAME, which are used when there is an error invoking another
routine.  Using notionally similar FUNCTION_* keys to mean my own
function seems pretty confusing (and also of questionable usefulness, as
you have commented).

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Re: Re: [PATCH] GET DIAGNOSTICS FUNCTION_NAME

От:

David Steele <david@pgmasters.net>

Дата:

7 марта 2018 г. в 17:46:41

On 3/5/18 10:09 PM, Yugo Nagata wrote:
> On Thu, 1 Mar 2018 14:29:58 -0800
> Andres Freund  wrote:
> 
>> Hi,
>>
>> On 2018-01-11 11:03:26 +0900, Yugo Nagata wrote:
>>> However, I don't inisist on this patch, so If anyone other don't need this
>>> feature, I'll withdraw this.
>>
>> Given this is where the discussion dried up more than a month ago I'm
>> inclined to mark this as rejected unless somebody wants to argue
>> otherwise?
> 
> I have no objection.

Marked as Rejected.

Regards,
-- 
-David
david@pgmasters.net