Re: Numeric multiplication overflow errors
Dean Rasheed <dean.a.rasheed@gmail.com>
From: Dean Rasheed <dean.a.rasheed@gmail.com>
To: David Rowley <dgrowleyml@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-07-02T10:55:47Z
Lists: pgsql-hackers
Attachments
- numeric-agg-sumX2-overflow-v3.patch (text/x-patch) patch v3
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
Commits
-
Fix numeric_mul() overflow due to too many digits after decimal point.
- f8abf6944b12 9.6.23 landed
- 54a0ec1bd6d5 10.18 landed
- 5763ef42c187 11.13 landed
- 357b66ef9470 12.8 landed
- f23a9b8a49af 13.4 landed
- 06883d58ff29 14.0 landed
- e7fc488ad67c 15.0 landed
-
Prevent numeric overflows in parallel numeric aggregates.
- f025f2390e13 15.0 landed