Re: [HACKERS] asynchronous execution - Mailing list pgsql-hackers

From Kyotaro HORIGUCHI
Subject Re: [HACKERS] asynchronous execution
Date
Msg-id 20170629.134551.108851183.horiguchi.kyotaro@lab.ntt.co.jp
Whole thread Raw
In response to Re: [HACKERS] asynchronous execution  (Antonin Houska <ah@cybertec.at>)
Responses Re: [HACKERS] asynchronous execution  (Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>)
List pgsql-hackers
Thank you for looking this.

At Wed, 28 Jun 2017 10:23:54 +0200, Antonin Houska <ah@cybertec.at> wrote in <4579.1498638234@localhost>
> Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp> wrote:
> 
> > The patch got conflicted. This is a new version just rebased to
> > the current master. Furtuer amendment will be taken later.
> 
> Can you please explain this part of make_append() ?
> 
> /* Currently async on partitioned tables is not available */
> Assert(nasyncplans == 0 || partitioned_rels == NIL);
> 
> I don't think the output of Append plan is supposed to be ordered even if the
> underlying relation is partitioned. Besides ordering, is there any other
> reason not to use the asynchronous execution?

It was just a developmental sentinel that will remind me later to
consider the declarative partitions since I didn't have an idea
of the differences (or the similarity) between appendrels and
partitioned_rels. It is never to say the condition cannot
make. I'll check it out and will support partitioned_rels sooner.
Sorry for having left it as it is.

> And even if there was some, the planner should ensure that executor does not
> fire the assertion statement above. The script attached shows an example how
> to cause the assertion failure.


regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center




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