Re: Lowering the ever-growing heap->pd_lower - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: Lowering the ever-growing heap->pd_lower
Date
Msg-id CAH2-Wzmi4t_umu7F30A+MC=gVEcXNLGLuWD5_FOgvGGa4bbhww@mail.gmail.com
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In response to Re: Lowering the ever-growing heap->pd_lower  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On Wed, Aug 4, 2021 at 7:39 AM Robert Haas <robertmhaas@gmail.com> wrote:
> How would it hurt?
>
> It's easy to see the harm caused by not shortening the line pointer
> array when it is possible to do so: we're using up space in the page
> that could have been made free. It's not so obvious to me what the
> downside of shortening it might be.

I think that that's probably true. That in itself doesn't seem like a
good enough reason to commit the patch.

Maybe this really won't be difficult for Matthias. I just want to see
some concrete testing, maybe with pgbench, or with an artificial test
case. Maybe something synthetic that shows a benefit measurable in
on-disk table size. Or at least the absence of any regressions.
Something.

-- 
Peter Geoghegan



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