Horton

Re: Lowering the ever-growing heap->pd_lower

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Matthias van de Meent <boekewurm+postgres@gmail.com>
Cc: John Naylor <john.naylor@enterprisedb.com>, Tom Lane <tgl@sss.pgh.pa.us>, Mark Dilger <mark.dilger@enterprisedb.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2021-05-18T19:33:30Z
Lists: pgsql-hackers 
On Tue, May 18, 2021 at 12:29 PM Matthias van de Meent
<boekewurm+postgres@gmail.com> wrote:
> PFA the updated version of this patch. Apart from adding line pointer
> truncation in PageRepairFragmentation (as in the earlier patches), I
> also altered PageTruncateLinePointerArray to clean up all trailing
> line pointers, even if it was the last item on the page.

Can you show a practical benefit to this patch, such as an improvement
in throughout or in efficiency for a given workload?

It was easy to see that having something was better than having
nothing at all. But things are of course different now that we have
PageTruncateLinePointerArray().

-- 
Peter Geoghegan

Commits

  1. Truncate line pointer array during heap pruning.

  2. Truncate line pointer array during VACUUM.