Thread: [PATCH] GET DIAGNOSTICS FUNCTION_NAME
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 <nagata@sraoss.co.jp>
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> 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.
>> 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
On Sun, 31 Dec 2017 17:54:06 +0900 (JST) Tatsuo Ishii <ishii@sraoss.co.jp> 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 <nagata@sraoss.co.jp>
> 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.
Yugo Nagata <nagata@sraoss.co.jp> 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
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
On Sun, 31 Dec 2017 11:57:02 -0500 Tom Lane <tgl@sss.pgh.pa.us> wrote: > Yugo Nagata <nagata@sraoss.co.jp> 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 <nagata@sraoss.co.jp>
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
On Thu, 1 Mar 2018 14:29:58 -0800 Andres Freund <andres@anarazel.de> 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 <nagata@sraoss.co.jp>
On 3/5/18 10:09 PM, Yugo Nagata wrote: > On Thu, 1 Mar 2018 14:29:58 -0800 > Andres Freund <andres@anarazel.de> 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