2017-12-15 4:43 GMT+01:00 Ashutosh Bapat <ashutosh.ba...@enterprisedb.com>:
> On Thu, Dec 14, 2017 at 10:16 PM, Pavel Stehule <pavel.steh...@gmail.com> > wrote: > > > > > > 2017-12-14 17:10 GMT+01:00 David G. Johnston <david.g.johns...@gmail.com > >: > >> > >> On Thu, Dec 14, 2017 at 8:22 AM, Merlin Moncure <mmonc...@gmail.com> > >> wrote: > >>> > >>> On Thu, Dec 14, 2017 at 8:38 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > >>> > Ashutosh Bapat <ashutosh.ba...@enterprisedb.com> writes: > >>> >> We allow a function to be invoked as part of PERFORM statement in > >>> >> plpgsql > >>> >> ... > >>> >> But we do not allow a procedure to be invoked this way > >>> > > >>> >> Procedures fit that category and like functions, I think, we should > >>> >> allow them be invoked directly without any quoting and CALL > >>> >> decoration. > >>> > > >>> > How is that going to work? What if the procedure tries to commit the > >>> > current transaction? > >>> > > >>> > IOW, this is not merely a syntactic-sugar question. > >>> > >>> BTW, We've already come to (near-but good enough) consensus that > >>> PERFORM syntax is really just unnecessary, and I submitted a patch to > >>> make it optional (which I really need to dust off and complete). > >> > >> > >> Except right now PERFORM doesn't exist in SQL and is a pl/pgsql keyword > to > >> specify a specific limited form of the SQL SELECT command. CALL is an > SQL > >> command. I don't see any real upside to allowing pl/pgsql to accept > >> omission of the command tag while SQL cannot - at least not without a > >> use-case describe why such syntax would be beneficial. And likely > those use > >> cases would revolve around some looping variant as opposed to a single > >> stand-alone, result-less, CALL. > >> > >> If we do keep "PERFORM" in the pl/pgsql vocab I'd consider the following > >> enhancement: > >> PERFORM func() => SELECT func() > >> PERFORM proc() => CALL proc() > > > > > > I don't like this idea - functions are not procedures - can be nice if it > > will be visible. > > > > There is a certain similarly between functions and procedures which > can not be denied, both take IN/OUT arguments and except SELECT/CALL > syntax decoration they are invoked similarly. Just to note: users have > been using function with void return value till now. > No, there are significant difference between SELECT and CALL - procedure is not a void function. > If we allow SELECT to be dropped while invoking a function through > PERFORM, why not to drop CALL for procedures similarly? > >From my perspective a PERFORM is not bad idea, because it is consistent in PLpgSQL. Again - I don't see more issues related to PERFORM - usually much more terrible is different system for OUT variables. This is a problem. Regards Pavel > > -- > Best Wishes, > Ashutosh Bapat > EnterpriseDB Corporation > The Postgres Database Company >
