Horton

Re: Parallelize correlated subqueries that execute within each worker

Zhihong Yu <zyu@yugabyte.com>

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From: Zhihong Yu <zyu@yugabyte.com>
To: James Coleman <jtc331@gmail.com>
Cc: Daniel Gustafsson <daniel@yesql.se>, pgsql-hackers <pgsql-hackers@postgresql.org>, Amit Kapila <amit.kapila16@gmail.com>
Date: 2021-09-07T15:06:00Z
Lists: pgsql-hackers

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  1. Windows support in pg_import_system_collations

  2. Remove pessimistic cost penalization from Incremental Sort

On Tue, Sep 7, 2021 at 6:17 AM James Coleman <jtc331@gmail.com> wrote:

> On Wed, Sep 1, 2021 at 7:06 AM Daniel Gustafsson <daniel@yesql.se> wrote:
> >
> > > On 7 May 2021, at 18:30, James Coleman <jtc331@gmail.com> wrote:
> >
> > > ..here we are now, and I finally have this patch cleaned up
> > > enough to share.
> >
> > This patch no longer applies to HEAD, can you please submit a rebased
> version?
>
> See attached.
>
> Thanks,
> James
>
Hi,
For v2-0002-Parallel-query-support-for-basic-correlated-subqu.patch :

+    * is when we're going to execute multiple partial parths in parallel

parths -> paths

        if (index->amcanparallel &&
-           rel->consider_parallel && outer_relids == NULL &&
-           scantype != ST_BITMAPSCAN)
+               rel->consider_parallel && outer_relids == NULL &&
+               scantype != ST_BITMAPSCAN)

the change above seems unnecessary since the first line of if condition
doesn't change.
Similar comment for the next hunk.

+            * It's not a partial path; it'a a full path that is executed
as a subquery.

it'a a -> it's a

+           /* rel->consider_parallel_rechecking_params = false; */
+           /* rel->partial_pathlist = NIL; */

The commented code can be taken out.

Cheers