Re: row filtering for logical replication

On Tue, Feb 1, 2022 at 12:07 PM Peter Smith <smithpb2250@gmail.com> wrote:
>
> On Sat, Jan 29, 2022 at 11:31 AM Andres Freund <andres@anarazel.de> wrote:
> >
> > Hi,
> >
> > Are there any recent performance evaluations of the overhead of row filters? I
> > think it'd be good to get some numbers comparing:
> >
> > 1) $workload with master
> > 2) $workload with patch, but no row filters
> > 3) $workload with patch, row filter matching everything
> > 4) $workload with patch, row filter matching few rows
> >
> > For workload I think it'd be worth testing:
> > a) bulk COPY/INSERT into one table
> > b) Many transactions doing small modifications to one table
> > c) Many transactions targetting many different tables
> > d) Interspersed DDL + small changes to a table
> >
>
> I have gathered performance data for the workload case (a):
>
> HEAD 46743.75
> v74 no filters 46929.15
> v74 allow 100% 46926.09
> v74 allow 75% 40617.74
> v74 allow 50% 35744.17
> v74 allow 25% 29468.93
> v74 allow 0% 22540.58
>
> PSA.
>
> This was tested using patch v74 and synchronous pub/sub. There are 1M
> INSERTS for publications using differing amounts of row filtering (or
> none).
>
> Observations:
> - There seems insignificant row-filter overheads (e.g. viz no filter
> and 100% allowed versus HEAD).
> - The elapsed time decreases linearly as there is less data getting replicated.
>

FYI - attached are the test steps I used in case anyone wants to try
to reproduce these results.

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Kind Regards,
Peter Smith.
Fujitsu Australia