Clarify old WAL files cannot be removed until they are summarized

Lists: pgsql-docs
From: Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
To: pgsql-docs(at)lists(dot)postgresql(dot)org
Subject: Clarify old WAL files cannot be removed until they are summarized
Date: 2024-10-17 17:25:15
Message-ID: fd0eb0a5-f43b-4e06-b450-cbca011b6cff@oss.nttdata.com
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Hi,

The documentation in wal.sgml explains that old WAL files cannot be
removed or recycled until they are archived (when WAL archiving is used)
or replicated (when using replication slots). However, it did not
mention that, similarly, old WAL files are also kept until they are summarized
if WAL summarization is enabled. Attached patch adds that clarification to
the documentation. Thought?

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

Attachment Content-Type Size
v1-0001-doc-Clarify-old-WAL-files-are-kept-until-they-are.patch text/plain 1.1 KB

From: Michael Paquier <michael(at)paquier(dot)xyz>
To: Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
Cc: pgsql-docs(at)lists(dot)postgresql(dot)org
Subject: Re: Clarify old WAL files cannot be removed until they are summarized
Date: 2024-12-11 00:18:48
Message-ID: Z1jaaLi2vq-Wpk9y@paquier.xyz
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On Fri, Oct 18, 2024 at 02:25:15AM +0900, Fujii Masao wrote:
> The documentation in wal.sgml explains that old WAL files cannot be
> removed or recycled until they are archived (when WAL archiving is used)
> or replicated (when using replication slots). However, it did not
> mention that, similarly, old WAL files are also kept until they are summarized
> if WAL summarization is enabled. Attached patch adds that clarification to
> the documentation. Thought?
>
> @@ -643,6 +643,8 @@
> until the situation is resolved. A slow or failed standby server that
> uses a replication slot will have the same effect (see
> <xref linkend="streaming-replication-slots"/>).
> + Similarly, if WAL summarization is enabled, old segments are kept
> + until they are summarized.
> </para>

Sounds like a good idea to me. I'd suggest to add a link to
runtime-config-wal-summarization as it is the first reference to WAL
summarization in this file.
--
Michael


From: Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
To: Michael Paquier <michael(at)paquier(dot)xyz>
Cc: pgsql-docs(at)lists(dot)postgresql(dot)org
Subject: Re: Clarify old WAL files cannot be removed until they are summarized
Date: 2024-12-12 15:08:06
Message-ID: 87716933-16fc-4b79-a4f6-59ffc06a76a1@oss.nttdata.com
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On 2024/12/11 9:18, Michael Paquier wrote:
> On Fri, Oct 18, 2024 at 02:25:15AM +0900, Fujii Masao wrote:
>> The documentation in wal.sgml explains that old WAL files cannot be
>> removed or recycled until they are archived (when WAL archiving is used)
>> or replicated (when using replication slots). However, it did not
>> mention that, similarly, old WAL files are also kept until they are summarized
>> if WAL summarization is enabled. Attached patch adds that clarification to
>> the documentation. Thought?
>>
>> @@ -643,6 +643,8 @@
>> until the situation is resolved. A slow or failed standby server that
>> uses a replication slot will have the same effect (see
>> <xref linkend="streaming-replication-slots"/>).
>> + Similarly, if WAL summarization is enabled, old segments are kept
>> + until they are summarized.
>> </para>
>
> Sounds like a good idea to me. I'd suggest to add a link to
> runtime-config-wal-summarization as it is the first reference to WAL
> summarization in this file.

Yes, that sounds like a good idea. I've updated the patch accordingly.

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

Attachment Content-Type Size
v2-0001-doc-Clarify-old-WAL-files-are-kept-until-they-are.patch text/plain 1.4 KB

From: Michael Paquier <michael(at)paquier(dot)xyz>
To: Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
Cc: pgsql-docs(at)lists(dot)postgresql(dot)org
Subject: Re: Clarify old WAL files cannot be removed until they are summarized
Date: 2024-12-13 00:12:12
Message-ID: Z1t73LZbGngJ1Vj3@paquier.xyz
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On Fri, Dec 13, 2024 at 12:08:06AM +0900, Fujii Masao wrote:
> Yes, that sounds like a good idea. I've updated the patch accordingly.

LGTM.
--
Michael


From: Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
To: Michael Paquier <michael(at)paquier(dot)xyz>
Cc: pgsql-docs(at)lists(dot)postgresql(dot)org
Subject: Re: Clarify old WAL files cannot be removed until they are summarized
Date: 2024-12-15 02:22:54
Message-ID: 6327bec4-f08f-4dcd-bfd9-6cc25a754462@oss.nttdata.com
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On 2024/12/13 9:12, Michael Paquier wrote:
> On Fri, Dec 13, 2024 at 12:08:06AM +0900, Fujii Masao wrote:
>> Yes, that sounds like a good idea. I've updated the patch accordingly.
>
> LGTM.

Pushed. Thanks!

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION