Re: [HACKERS] why not parallel seq scan for slow functions - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: [HACKERS] why not parallel seq scan for slow functions
Date
Msg-id CAA4eK1LtQ8dVHhO+s4PGj_A-ZMCnXOziF1QPn-R1PGxRxHJDyw@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] why not parallel seq scan for slow functions  (Jeff Janes <jeff.janes@gmail.com>)
List pgsql-hackers
On Mon, Jul 24, 2017 at 9:21 PM, Jeff Janes <jeff.janes@gmail.com> wrote:
> On Sat, Jul 22, 2017 at 8:53 PM, Amit Kapila <amit.kapila16@gmail.com>
> wrote:
>>
>> On Thu, Jul 13, 2017 at 7:38 AM, Amit Kapila <amit.kapila16@gmail.com>
>> wrote:
>> > On Wed, Jul 12, 2017 at 11:20 PM, Jeff Janes <jeff.janes@gmail.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



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