Hi,
For the record, here is the relevant part of the Incremental Sort patch
series, updating add_partial_path and add_partial_path_precheck to also
consider startup cost.
The changes in the first two patches are pretty straight-forward, plus
there's a proposed optimization in the precheck functi
On Fri, Oct 4, 2019 at 8:36 AM Robert Haas wrote:
>
> On Wed, Oct 2, 2019 at 10:22 AM James Coleman wrote:
> > In all cases I've been starting with:
> >
> > set enable_hashjoin = off;
> > set enable_nestloop = off;
> > set max_parallel_workers_per_gather = 4;
> > set min_parallel_index_scan_size
On Wed, Oct 2, 2019 at 10:22 AM James Coleman wrote:
> In all cases I've been starting with:
>
> set enable_hashjoin = off;
> set enable_nestloop = off;
> set max_parallel_workers_per_gather = 4;
> set min_parallel_index_scan_size = 0;
> set min_parallel_table_scan_size = 0;
> set parallel_setup_c
On Sat, Sep 28, 2019 at 7:21 PM James Coleman wrote:
> Now the trick is to figure out a way to demonstrate it in test :)
>
> Basically we need:
> Path A: Can short circuit with LIMIT but has high total cost
> Path B: Can’t short circuit with LIMIT but has lower total cost
>
> (Both must be paralle
On Saturday, September 28, 2019, Tomas Vondra
wrote:
> On Sat, Sep 28, 2019 at 12:16:05AM -0400, Robert Haas wrote:
>
>> On Fri, Sep 27, 2019 at 2:24 PM James Coleman wrote:
>>
>>> Over in the incremental sort patch discussion we found [1] a case
>>> where a higher cost plan ends up being chosen
On Sat, Sep 28, 2019 at 12:16:05AM -0400, Robert Haas wrote:
On Fri, Sep 27, 2019 at 2:24 PM James Coleman wrote:
Over in the incremental sort patch discussion we found [1] a case
where a higher cost plan ends up being chosen because a low startup
cost partial path is ignored in favor of a lowe
On Fri, Sep 27, 2019 at 2:24 PM James Coleman wrote:
> Over in the incremental sort patch discussion we found [1] a case
> where a higher cost plan ends up being chosen because a low startup
> cost partial path is ignored in favor of a lower total cost partial
> path and a limit is a applied on to
Over in the incremental sort patch discussion we found [1] a case
where a higher cost plan ends up being chosen because a low startup
cost partial path is ignored in favor of a lower total cost partial
path and a limit is a applied on top of that which would normal favor
the lower startup cost plan
