Horton

Re: Parallel Full Hash Join

Thomas Munro <thomas.munro@gmail.com>

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From: Thomas Munro <thomas.munro@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-03-06T01:30:33Z
Lists: pgsql-hackers

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On Tue, Mar 2, 2021 at 11:27 PM Thomas Munro <thomas.munro@gmail.com> wrote:
> On Fri, Feb 12, 2021 at 11:02 AM Melanie Plageman
> <melanieplageman@gmail.com> wrote:
> > I just attached the diff.
>
> Squashed into one patch for the cfbot to chew on, with a few minor
> adjustments to a few comments.

I did some more minor tidying of comments and naming.  It's been on my
to-do-list to update some phase names after commit 3048898e, and while
doing that I couldn't resist the opportunity to change DONE to FREE,
which somehow hurts my brain less, and makes much more obvious sense
after the bugfix in CF #3031 that splits DONE into two separate
phases.  It also pairs obviously with ALLOCATE.  I include a copy of
that bugix here too as 0001, because I'll likely commit that first, so
I rebased the stack of patches that way.  0002 includes the renaming I
propose (master only).  Then 0003 is Melanie's patch, using the name
SCAN for the new match bit scan phase.  I've attached an updated
version of my "phase diagram" finger painting, to show how it looks
with these three patches.  "scan*" is new.

Commits

  1. Remove overzealous assertion from PHJ.

  2. Remove comment obsoleted by 11c2d6fd.

  3. Parallel Hash Full Join.

  4. Improve the naming of Parallel Hash Join phases.

  5. Update the names of Parallel Hash Join phases.

  6. Add BarrierArriveAndDetachExceptLast().

  7. Mop-up for wait event naming issues.

  8. Push tuple limits through Gather and Gather Merge.