On Wed, Jun 24, 2020 at 2:44 AM Amit Kapila wrote:
> So, that leads to loops as 2 on "Parallel Seq Scan" and "Nested Loop" nodes.
> Does this make sense now?
Yes, I think we're on the same page. Thanks for the additional details.
It turns out that the plan I sent at the top of the thread is ac
On Tue, Jun 23, 2020 at 12:55 AM Maciek Sakrejda wrote:
>
> Hello,
>
> I had some questions about the behavior of some accounting in parallel
> EXPLAIN plans. Take the following plan:
>
>
..
>
> The Nested Loop here aggregates data for metrics like `buffers read`
> from its workers, and to calcula
On Wed, Jun 24, 2020 at 12:41 PM Maciek Sakrejda wrote:
>
> On Tue, Jun 23, 2020 at 7:55 PM Amit Kapila wrote:
> > > I don't see any other reason for
> > > looping over the NL node itself in this plan. The Gather itself
> > > doesn't do any real looping, right?
> >
> > It is right that Gather doe
On Tue, Jun 23, 2020 at 7:55 PM Amit Kapila wrote:
> > I don't see any other reason for
> > looping over the NL node itself in this plan. The Gather itself
> > doesn't do any real looping, right?
>
> It is right that Gather doesn't do looping but Parallel Seq Scan node does so.
Sorry, I still don
On Wed, Jun 24, 2020 at 3:18 AM Maciek Sakrejda wrote:
>
> On Tue, Jun 23, 2020 at 2:57 AM Amit Kapila wrote:
> > I don't think this is an odd situation because in this case, child
> > nodes like "Nested Loop" and "Parallel Seq Scan" has a value of
> > 'loops' as 3. So, to get the correct stats
On Tue, Jun 23, 2020 at 2:57 AM Amit Kapila wrote:
> I don't think this is an odd situation because in this case, child
> nodes like "Nested Loop" and "Parallel Seq Scan" has a value of
> 'loops' as 3. So, to get the correct stats at those nodes, you need
> to divide it by 3 whereas, at Gather no
On Tue, Jun 23, 2020 at 12:55 AM Maciek Sakrejda wrote:
>
> Hello,
>
> I had some questions about the behavior of some accounting in parallel
> EXPLAIN plans. Take the following plan:
>
> ```
> Gather (cost=1000.43..750173.74 rows=2 width=235) (actual
> time=1665.122..1665.122 rows=0 loops=1)
>
