public inbox for [email protected]  
help / color / mirror / Atom feed
From: Melanie Plageman <[email protected]>
To: Kirill Reshke <[email protected]>
Cc: Andrey Borodin <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Heikki Linnakangas <[email protected]>
Subject: Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM on-access)
Date: Tue, 2 Sep 2025 17:52:37 -0400
Message-ID: <CAAKRu_a2zU7672weJCGzAE2K44cCwnvsb-BwPh8ET3n1bsKfPQ@mail.gmail.com> (raw)
In-Reply-To: <CALdSSPhu7WZd+EfQDha1nz=DC93OtY1=UFEdWwSZsASka_2eRQ@mail.gmail.com>
References: <CAAKRu_ZMw6Npd_qm2KM+FwQ3cMOMx1Dh3VMhp8-V7SOLxdK9-g@mail.gmail.com>
	<CAAKRu_YXP1Us41fkZJeBK5SSj5whNC0C9fZNT6Brdtm+F0agpg@mail.gmail.com>
	<CAAKRu_bAR5uCfjuc06vc_xrZjNCJLs493NgHjTOUDso9qGdE0w@mail.gmail.com>
	<CAAKRu_ac4vUdU-U3ax8j=N8y2OM9-pbFZhafLVfzDOM8MtzvvA@mail.gmail.com>
	<[email protected]>
	<CAAKRu_a-aVGxNEdkJt+96HGryQXuQNuXe+PhR0KcnUhXSOPBJw@mail.gmail.com>
	<[email protected]>
	<CAAKRu_ZH8kL0Zm0j7m7DC9fzk7ru7yf9rm2pEQRvx1iXX25aPQ@mail.gmail.com>
	<CAAKRu_bGCgUuhmy1Mzkw3yCmbGcjNQAjV=OmjuW6hz90PuXKWA@mail.gmail.com>
	<CALdSSPhAU56g1gGVT0+wG8RrSWE6qW8TOfNJS1HNAWX6wPgbFA@mail.gmail.com>
	<CAAKRu_YD0ecXeAh+DmJpzQOJwcRzmMyGdcc5W_0pEF78rYSJkQ@mail.gmail.com>
	<CALdSSPhu7WZd+EfQDha1nz=DC93OtY1=UFEdWwSZsASka_2eRQ@mail.gmail.com>

On Thu, Aug 28, 2025 at 5:12 AM Kirill Reshke <[email protected]> wrote:
>
> I did micro git-blame research here. I spotted only one related change
> [0]. Looks like before this change pin was indeed needed.
> But not after this change, so this visibilitymap_pin is just an oversight?
> Related thread is [1]. I quickly checked the discussion in this
> thread, and it looks like no one was bothered about these lines or VM
> logging changes (in this exact pin buffer aspect). The discussion was
> of other aspects of this commit.

Wow, thanks so much for doing that research. Looking at it myself, it
does indeed seem like just an oversight. It isn't harmful since it
won't take another pin, but it is confusing, so I think we should at
least remove it in master. I'm not as sure about back branches.

I would like someone to confirm that there is no way we could end up
with a different block of the VM containing the vm bits for a heap
block during recovery than during normal operation.

- Melanie





view thread (143+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
  Subject: Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM on-access)
  In-Reply-To: <CAAKRu_a2zU7672weJCGzAE2K44cCwnvsb-BwPh8ET3n1bsKfPQ@mail.gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox