From: Pavel Luzanov <p.luzanov@postgrespro.ru>
To: Bruce Momjian <bruce@momjian.us>
Cc: David G. Johnston <david.g.johnston@gmail.com>
Cc: pluzanov@postgrespro.ru
Cc: pgsql-docs@lists.postgresql.org
Subject: Re: max_wal_size
Date: Tue, 2 Jun 2020 23:42:01 +0300
Message-ID: <26906a54-d7cb-2f8e-eed7-e31660024694@postgrespro.ru> (raw)
In-Reply-To: <20200602193547.GA26240@momjian.us>
References: <159057129673.7025.17016799863173731176@wrigleys.postgresql.org>
<CAKFQuwZOwfUwOxNh5KjUjCSFaecUWxtHEbPHEK8CJF1+zn9Bjg@mail.gmail.com>
<92491c6d07a3216ef2caee8ef55c02b5@postgrespro.ru>
<CAKFQuwYOGSRbcWnSEo7vp7JJktdH9rKJM0T8Q3B6J0QJcq==hA@mail.gmail.com>
<8aac88e2a22cd84e50ee1a2bcf3da9b7@postgrespro.ru>
<CAKFQuwY=eGGGe7E9xHkdR+8YnKXeA8xp-qfRMGFJrs-Hsb_D5Q@mail.gmail.com>
<b8e12875ebec9e6d3107df5fa1129e1e@postgrespro.ru>
<20200602193547.GA26240@momjian.us>
Hello,
On 02.06.2020 22:35, Bruce Momjian wrote:
> On Thu, May 28, 2020 at 12:21:14PM +0300, p.luzanov@postgrespro.ru wrote:
>> WAL |-----------|-----+-----|-----+-----|-----+----->
>>
>> a b c
>> CP +-----+ +-----+ +-----+
>> b e b e b e
>>
>> Checkpointer process for point A starts at a(b) and ends at a(e).
>> At the end of the work, CP makes a WAL record(plus symbol on WAL line).
>>
>> Back to the max_wal_size description:
>> "Maximum size to let the WAL grow to between automatic WAL checkpoints."
>>
>> As I understand now, this is true when we talk about the checkpoint as a
>> process.
>> "Maximum size to let the WAL grow to between a(b) and b(e), between b(b) and c
>> (e), etc".
> What if we say:
>
> "Maximum size to let the WAL grow during automatic WAL checkpoints."
>
> That highlights the "process" part.
>
Really, "during" is associated with the process, while "between" with
points.
If there is no objection, simpe patch attached.
-----
Pavel Luzanov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
Attachments:docs_max_wal_size.patch (text/x-patch, 602B) downloaddiff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgmlindex 4eef970d41..7398806203 100644--- a/doc/src/sgml/config.sgml+++ b/doc/src/sgml/config.sgml@@ -3085,7 +3085,7 @@ include_dir 'conf.d'
</term>
<listitem>
<para>
- Maximum size to let the WAL grow to between automatic WAL+ Maximum size to let the WAL grow during automatic WAL
checkpoints. This is a soft limit; WAL size can exceed
<varname>max_wal_size</varname> under special circumstances, such as
heavy load, a failing <varname>archive_command</varname>, or a high
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To: pgsql-docs@postgresql.org
Cc: p.luzanov@postgrespro.ru, bruce@momjian.us, david.g.johnston@gmail.com, pluzanov@postgrespro.ru, pgsql-docs@lists.postgresql.org
Subject: Re: max_wal_size
In-Reply-To: <26906a54-d7cb-2f8e-eed7-e31660024694@postgrespro.ru>
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