On Sun, Nov 12, 2017 at 9:18 AM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> On Sat, Oct 21, 2017 at 8:09 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> On Tue, Oct 17, 2017 at 7:27 AM, Thomas Munro
>> <thomas.munro@enterprisedb.com> wrote:
>>
>> I don't think overloading force_parallel_mode is a good idea, but
>> having some other GUC for this seems OK to me. Not sure I like
>> multiplex_gather, though.
>
> How about parallel_leader_participation = on|off? The attached
> version has it that way, and adds regression tests to exercise on, off
> and off-but-couldn't-start-any-workers for both kinds of gather node.
>
> I'm not sure why node->need_to_rescan is initialised by both
> ExecGatherInit() and ExecGather(). Only the latter's value matters,
> right?
>
I don't see anything like need_to_rescan in the GatherState node. Do
you intend to say need_to_scan_locally? If yes, then I think whatever
you said is right.
> I've added this to the January Commitfest.
>
+1 to this idea. Do you think such an option at table level can be
meaningful? We have a parallel_workers as a storage option for
tables, so users might want leader to participate in parallelism only
for some of the tables.
--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com
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