Re: WIP: [[Parallel] Shared] Hash

From: Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>
To: Oleg Golovanov <rentech(at)mail(dot)ru>
Cc: Peter Geoghegan <pg(at)bowt(dot)ie>, Rafia Sabih <rafia(dot)sabih(at)enterprisedb(dot)com>, Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com>, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, Robert Haas <robertmhaas(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>
Subject: Re: WIP: [[Parallel] Shared] Hash
Date: 2017-04-26 23:03:48
Views: Raw Message | Whole Thread | Download mbox
Lists: pgsql-hackers

On Thu, Apr 27, 2017 at 5:13 AM, Oleg Golovanov <rentech(at)mail(dot)ru> wrote:
> Can you actualize your patch set? The error got from
> 0010-hj-parallel-v12.patch.

I really should get around to setting up a cron job to tell me about
that. Here's a rebased version.

The things currently on my list for this patch are:

1. Implement the skew optimisation.
2. Consider Andres's suggestion of splitting MultiExecHash into two
functions, serial and parallel version, rather than having all those
conditional blocks in there.
3. Figure out whether the shared BufFile stuff I propose would work
well for Peter Geoghegan's parallel tuple sort patch, by trying it
(I've made a start, more soon).
4. Figure out how the costing model needs to be tweaked, probably
based on experimentation.

I'm taking a short break to work on other things right now but will
post a version with those changes soon.

Thomas Munro

Attachment Content-Type Size
parallel-shared-hash-v13.tgz application/x-gzip 63.2 KB

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message David Rowley 2017-04-26 23:09:51 Re: Foreign Join pushdowns not working properly for outer joins
Previous Message Tom Lane 2017-04-26 22:02:20 Re: Logical replication in the same cluster