Re: [patch] CLUSTER blocks scanned progress reporting

From: Matthias van de Meent <boekewurm+postgres(at)gmail(dot)com>
To: Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [patch] CLUSTER blocks scanned progress reporting
Date: 2020-11-26 16:45:21
Message-ID: CAEze2WiwvfktwML1KRffV3h5idP3ynA=ES9LvddhUojHJQKzCg@mail.gmail.com
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On Thu, 26 Nov 2020 at 00:55, Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com> wrote:
>
> + * A heap scan need not return tuples for the last page it has
> + * scanned. To ensure that heap_blks_scanned is equivalent to
> + * total_heap_blks after the table scan phase, this parameter
> + * is manually updated to the correct value when the table scan
> + * finishes.
>
> So it's better to update this comment a bit? For example,
>
> If the scanned last pages are empty, it's possible to go to the next phase
> while heap_blks_scanned != heap_blks_total. To ensure that they are
> equivalet after the table scan phase, this parameter is manually updated
> to the correct value when the table scan finishes.
>

PFA a patch with updated message and comment. I've reworded the
messages to specifically mention empty pages and the need for setting
heap_blks_scanned = total_heap_blks explicitly.

Feel free to update the specifics, other than that I think this is a
complete fix for the issues at hand.

Regards,

Matthias van de Meent

Attachment Content-Type Size
v3-0001-Fix-CLUSTER-progress-reporting-of-number-of-block.patch text/x-patch 3.1 KB

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