2011/5/10 Bruce Momjian <bruce@momjian.us>:
> Christopher Browne wrote:
>> > Multiple resultsets in one call would be a good thing, though, no?
>> >
>> > cheers
>>
>> I *thought* the purpose of having stored procedures was to allow a
>> substrate supporting running multiple transactions, so it could do
>> things like:
>> - Managing vacuums
>> - Managing transactions
>> - Replacing some of the need for dblink.
>> - Being an in-DB piece that could manage LISTENs
>>
>> It seems to be getting "bikeshedded" into something with more
>> "functional argument functionality" than stored functions.
>>
>> I think we could have a perfectly successful implementation of "stored
>> procedures" that supports ZERO ability to pass arguments in or out.
>> That's quite likely to represent a good start.
>
> I am kind of confused too, particularly with the CALL syntax. I thought
> our function call usage was superior in every way to CALL, so why
> implement CALL? I assume for SQL-standards compliance, right? Does
> multiple result sets require CALL? I assume autonomous transactions
> don't require CALL.
>
no - you are little bit confused :). CALL and function execution
shares nothing. There is significant differences between function and
procedure. Function is called only from executor - from some plan, and
you have to know a structure of result before run. The execution of
CALL is much simple - you just execute code - without plan and waiting
for any result - if there is.
> Are we assuming no one is going to want a function that allows multiple
> result sets or autonomous transactions? That seems unlikely. I would
> think CALL is independent of those features. Maybe we need those
> features to support SQL-standard CALL, and we will just add those
> features to functions too.
>
We can use a SETOF cursors for returning a multiple result sets now.
But there are a few complications:
a) The client should to wait for finish of all sets from multiple
result sets - minimally in PL/pgSQL
b) client 'psql' doesn't support a unpacking result when result is
multiple result set
c) The using cursors isn't too comfortable - in comparation to MS SQL or MySQL
Regards
Pavel
> --
> Bruce Momjian <bruce@momjian.us> http://momjian.us
> EnterpriseDB http://enterprisedb.com
>
> + It's impossible for everything to be true. +
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