Re: Weird return-value from pg_get_function_identity_arguments() oncertain aggregate functions?
| От | David G. Johnston |
|---|---|
| Тема | Re: Weird return-value from pg_get_function_identity_arguments() oncertain aggregate functions? |
| Дата | |
| Msg-id | CAKFQuwaMpCy4cmpLriLusw=iawCUB1F0wgjH_dFpu3VXB=Wjug@mail.gmail.com обсуждение исходный текст |
| Ответ на | Weird return-value from pg_get_function_identity_arguments() oncertain aggregate functions? (P O'Toole <P.OToole@uwyo.edu>) |
| Ответы |
Re: Weird return-value from pg_get_function_identity_arguments() oncertain aggregate functions?
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| Список | pgsql-bugs |
According to the System Information Functions docs, pg_get_function_identity_
arguments(OID) should simply "get argument list to identify a function (without default values)", but one example of how it behaves strangely is that:
SELECT pg_get_function_identity_
arguments('pg_catalog. percentile_disc(DOUBLE PRECISION[], ANYELEMENT)'::REGPROCEDURE)
FWIW a simple \dfS percentile* will elicit the same description.
I suppose it depends on what you are using the output for - the (percentile*) functions that are decorated with ORDER BY are exclusively aggregate, as opposed to standard, functions.
An ORDER BY is not a "default value" so we aren't really contradicting the docs - though seeing ORDER BY in a function signature is a surprise to me too...but reading the doc for CREATE AGGREGATE the SQL command syntax is:
CREATE AGGREGATE name ( [ [ argmode ] [ argname ] arg_data_type [ , ... ] ]
ORDER BY [ argmode ] [ argname ] arg_data_type [ , ... ] )
So I'd have to say this is working correctly.
I seem to recall some recent (last few weeks) discussion regarding aggregates vs functions in the information schema. That may prove to be enlightening but at the moment I don't have time to go look for and review it.
David J.
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