Re: [PATCH] Add extra statistics to explain for Nested Loop

On Wed, Apr 14, 2021 at 4:57 PM <e.sokolova@postgrespro.ru> wrote:
>
> Thank you for working on this issue. Your comments helped me make this
> patch more correct.
>
> > Lines with "colon" format shouldn't use equal signs, and should use two
> > spaces
> > between fields.
> Done. Now extra line looks like "Loop min_rows: %.0f  max_rows: %.0f
> total_rows: %.0f" or "Loop min_time: %.3f  max_time: %.3f  min_rows:
> %.0f  max_rows: %.0f  total_rows: %.0f".
>
> > Since this is now on a separate line, the "if (nloops > 1 &&
> > es->verbose)"
> > can be after the existing "if (es->timing)", and shouldn't need its own
> > "if (es->timing)".  It should conditionally add a separate line, rather
> > than
> > duplicating the "(actual.*" line.
> >
> >> -                    if (es->timing)
> >> +                    if (nloops > 1 && es->verbose)
> New version of patch contains this correction. It helped make the patch
> shorter.
>
> > In non-text mode, think you should not check "nloops > 1".  Rather,
> > print the
> > field as 0.
> The fields will not be zeros. New line will almost repeat the line with
> main sttistics.
>
> > I think the labels in non-text format should say "Loop Min Time" or
> > similar.
> >
> > And these variables should have a loop_ prefix like loop_min_t ?
> There are good ideas. I changed it.
>
> I apply new version of this patch. I hope it got better.
> Please don't hesitate to share any thoughts on this topic.

The patch does not apply on Head, I'm changing the status to "Waiting
for Author":
1 out of 2 hunks FAILED -- saving rejects to file
src/test/regress/expected/partition_prune.out.rej
patching file src/test/regress/sql/partition_prune.sql
Hunk #1 FAILED at 467.
Hunk #2 succeeded at 654 (offset -3 lines).
1 out of 2 hunks FAILED -- saving rejects to file
src/test/regress/sql/partition_prune.sql.rej

Please post a new patch rebased on head.

Regards,
Vignesh