Re: Performance degradation of REFRESH MATERIALIZED VIEW - Mailing list pgsql-hackers

From Masahiko Sawada
Subject Re: Performance degradation of REFRESH MATERIALIZED VIEW
Date
Msg-id CAD21AoAn22_10KtHt+7YoRp_46fOA04O9ONN1uVWkCpnmjwKQQ@mail.gmail.com
Whole thread Raw
In response to Re: Performance degradation of REFRESH MATERIALIZED VIEW  (Tomas Vondra <tomas.vondra@enterprisedb.com>)
List pgsql-hackers
On Mon, Apr 26, 2021 at 10:31 PM Tomas Vondra
<tomas.vondra@enterprisedb.com> wrote:
>
> Hi,
>
> I took a look at this today, as I committed 39b66a91b back in January. I
> can reproduce the issue, with just 1M rows the before/after timings are
> roughly 480ms and 620ms on my hardware.
>
> Unfortunately, the v3 patch does not really fix the issue for me. The
> timing with it applied is ~610ms so the improvement is only minimal.

Since the reading vmbuffer is likely to hit on the shared buffer
during inserting frozen tuples, I think the improvement would not be
visible with a few million tuples depending on hardware. But it might
not be as fast as before commit 39b66a91b since we read vmbuffer at
least per insertion.

Regards,

-- 
Masahiko Sawada
EDB:  https://www.enterprisedb.com/



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