Re: Proposal - asynchronous functions

On Tue, Apr 26, 2011 at 9:24 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Tue, Apr 26, 2011 at 10:02 AM, David Fetter <david(at)fetter(dot)org> wrote:
>> On Tue, Apr 26, 2011 at 04:17:48PM +0300, Sim Zacks wrote:
>>> On 04/26/2011 03:15 PM, Merlin Moncure wrote:
>>>
>>> >On Tue, Apr 26, 2011 at 3:28 AM, Sim Zacks<sim(at)compulab(dot)co(dot)il>  wrote:
>>> >>Asynchronous functions
>>> >>
>>> >>*Problem*
>>> >>Postgresql does not have support for asynchronous function calls.
>>> >Well, there is asynchronous support from the client of course.  Thus
>>> >you can set up a asynchronous call back to the database with dblink.
>>> >There is some discussion about formalizing this feature -- you might
>>> >want to read up on autonomous transactions and how they might be used
>>> >to do what you are proposing.
>>> >
>>> >merlin
>>> I am looking for specifically server support and not client support.
>>> Part of the proposal is that if the client goes away, it will still
>>> continue to finish.
>>
>> This is exactly autonomous transactions.  Please read this thread to
>> see how.
>>
>> http://archives.postgresql.org/pgsql-hackers/2008-01/msg00893.php
>
> It's not the same thing at all.  An autonomous function is (or appears
> to be) two simultaneous toplevel transactions within the same backend.
>  This is a request for an *asynchronous* function, which would run
> concurrently with foreground processing.

It's not exactly the same, but in the greater spirit of things I think
David is correct. If you make async dblink call, you get parallel
processing from a single function entry point. Autonomous
transaction implementations I've heard are basically taking this
approach and de-kludging it, and give you a lot of the same stuff,
like being able to do work in parallel. I'm curious if the feature
meets the OP's requirements.

merlin