Re: why not parallel seq scan for slow functions

On Mon, Jul 24, 2017 at 9:21 PM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
> On Sat, Jul 22, 2017 at 8:53 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
> wrote:
>>
>> On Thu, Jul 13, 2017 at 7:38 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
>> wrote:
>> > On Wed, Jul 12, 2017 at 11:20 PM, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
>> > wrote:
>> >>
>> >>
>> >>
>> >> Setting parallel_workers to 8 changes the threshold for the parallel to
>> >> even
>> >> be considered from parellel_tuple_cost <= 0.0049 to <= 0.0076. So it
>> >> is
>> >> going in the correct direction, but not by enough to matter.
>> >>
>> >
>> > You might want to play with cpu_tuple_cost and or seq_page_cost.
>> >
>>
>> I don't know whether the patch will completely solve your problem, but
>> this seems to be the right thing to do. Do you think we should stick
>> this for next CF?
>
>
> It doesn't solve the problem for me, but I agree it is an improvement we
> should commit.
>

Okay, added the patch for next CF.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com