Re: postgres_fdw vs. force_parallel_mode on ppc - Mailing list pgsql-hackers

From Tom Lane
Subject Re: postgres_fdw vs. force_parallel_mode on ppc
Date
Msg-id 7505.1457108261@sss.pgh.pa.us
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In response to Re: postgres_fdw vs. force_parallel_mode on ppc  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: postgres_fdw vs. force_parallel_mode on ppc
List pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Fri, Mar 4, 2016 at 11:03 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Well, that would make the function more complicated, but maybe it's a
>> better answer.  On the other hand, we know that the stats updates are
>> delivered in a deterministic order, so why not simply replace the
>> existing test in the wait function with one that looks for the truncation
>> updates?  If we've gotten those, we must have gotten the earlier ones.

> I'm not sure if that's actually true with parallel mode.  I'm pretty
> sure the earlier workers will have terminated before the later ones
> start, but is that enough to guarantee that the stats collector sees
> the messages in that order?

Huh?  Parallel workers are read-only; what would they be doing sending
any of these messages?
        regards, tom lane



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