Re: Numeric multiplication overflow errors - Mailing list pgsql-hackers

From Dean Rasheed
Subject Re: Numeric multiplication overflow errors
Date
Msg-id CAEZATCV2cisoKhGkbCyUGsfgBN66SVXocqbv6DpF9vCBs2QoxA@mail.gmail.com
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In response to Re: Numeric multiplication overflow errors  (David Rowley <dgrowleyml@gmail.com>)
Responses Re: Numeric multiplication overflow errors
List pgsql-hackers
On Fri, 2 Jul 2021 at 10:24, David Rowley <dgrowleyml@gmail.com> wrote:
>
> I ran this again with a few different worker counts after tuning a few
> memory settings so there was no spilling to disk and so everything was
> in RAM. Mostly so I could get consistent results.
>
> Here's the results. Average over 3 runs on each:
>
> Workers Master Patched Percent
> 8            11094.1 11084.9 100.08%
> 16           8711.4  8562.6   101.74%
> 32           6961.4  6726.3  103.50%
> 64           6137.4  5854.8  104.83%
> 128         6090.3  5747.4  105.96%
>

Thanks for testing again. Those are nice looking results, and are much
more in line with what I was seeing.

> So the gains are much less at lower worker counts.  I think this is
> because most of the gains are in the serial part of the plan and with
> higher worker counts that part of the plan is relatively much bigger.
>
> So likely performance isn't too critical here, but it is something to
> keep in mind.
>

Yes, agreed. I suspect there's not much more that can be shaved off
this particular piece of code now though. Here's an update with the
last set of changes discussed.

Regards,
Dean

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