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2020-06-03 43e592c706 53f32ea4d3 doc: Move wal_init_zero and wal_recycle descriptions to proper section.
* wal_init_zero and wal_recycle
@ 2020-05-27 03:27 Fujii Masao <masao.fujii@oss.nttdata.com>
2020-05-27 07:08 ` Re: wal_init_zero and wal_recycle Simon Riggs <simon@2ndquadrant.com>
0 siblings, 1 reply; 6+ messages in thread
From: Fujii Masao @ 2020-05-27 03:27 UTC (permalink / raw)
To: pgsql-docs@lists.postgresql.org
Hi,
The group of wal_init_zero and wal_recycle is WAL_SETTINGS in guc.c,
but their descriptions are located in "19.6. Replication"/"19.6.1. Sending
Servers" section. This seems a documentation bug. They should be located
in "19.5. Write Ahead Log"/"19.5.1. Settings". Thought?
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: wal_init_zero and wal_recycle
2020-05-27 03:27 wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2020-05-27 07:08 ` Simon Riggs <simon@2ndquadrant.com>
2020-05-27 23:43 ` Re: wal_init_zero and wal_recycle Thomas Munro <thomas.munro@gmail.com>
0 siblings, 1 reply; 6+ messages in thread
From: Simon Riggs @ 2020-05-27 07:08 UTC (permalink / raw)
To: Fujii Masao <masao.fujii@oss.nttdata.com>; +Cc: pgsql-docs@lists.postgresql.org
On Wed, 27 May 2020 at 04:27, Fujii Masao <masao.fujii@oss.nttdata.com>
wrote:
> Hi,
>
> The group of wal_init_zero and wal_recycle is WAL_SETTINGS in guc.c,
> but their descriptions are located in "19.6. Replication"/"19.6.1. Sending
> Servers" section. This seems a documentation bug. They should be located
> in "19.5. Write Ahead Log"/"19.5.1. Settings". Thought?
>
+1
Why are there two settings for the same thing (COW support)?
Would we really want to allow setting one but not the other?
--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/;
Mission Critical Databases
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: wal_init_zero and wal_recycle
2020-05-27 03:27 wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
2020-05-27 07:08 ` Re: wal_init_zero and wal_recycle Simon Riggs <simon@2ndquadrant.com>
@ 2020-05-27 23:43 ` Thomas Munro <thomas.munro@gmail.com>
2020-05-29 04:13 ` Re: wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
0 siblings, 1 reply; 6+ messages in thread
From: Thomas Munro @ 2020-05-27 23:43 UTC (permalink / raw)
To: Simon Riggs <simon@2ndquadrant.com>; +Cc: Fujii Masao <masao.fujii@oss.nttdata.com>; pgsql-docs@lists.postgresql.org
On Wed, May 27, 2020 at 7:09 PM Simon Riggs <simon@2ndquadrant.com> wrote:
> On Wed, 27 May 2020 at 04:27, Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
>>
>> Hi,
>>
>> The group of wal_init_zero and wal_recycle is WAL_SETTINGS in guc.c,
>> but their descriptions are located in "19.6. Replication"/"19.6.1. Sending
>> Servers" section. This seems a documentation bug. They should be located
>> in "19.5. Write Ahead Log"/"19.5.1. Settings". Thought?
>
>
> +1
>
> Why are there two settings for the same thing (COW support)?
> Would we really want to allow setting one but not the other?
In the long discussion[1] we decided to invent GUCs that tell you
precisely what they do, rather than trying to have a mysterious "COW
filesystem mode", given the apparent lack of COW filesystem expertise
in the thread (for example: claims, theories and data about ZFS were
presented, but do they also apply to BTRFS, APFS, ReFS, ...? I dunno,
and no one showed up with more information on that.)
[1] https://www.postgresql.org/message-id/flat/CACPQ5Fo00QR7LNAcd1ZjgoBi4y97%2BK760YABs0vQHH5dLdkkMA%40m...
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: wal_init_zero and wal_recycle
2020-05-27 03:27 wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
2020-05-27 07:08 ` Re: wal_init_zero and wal_recycle Simon Riggs <simon@2ndquadrant.com>
2020-05-27 23:43 ` Re: wal_init_zero and wal_recycle Thomas Munro <thomas.munro@gmail.com>
@ 2020-05-29 04:13 ` Fujii Masao <masao.fujii@oss.nttdata.com>
2020-06-02 05:25 ` Re: wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
0 siblings, 1 reply; 6+ messages in thread
From: Fujii Masao @ 2020-05-29 04:13 UTC (permalink / raw)
To: Thomas Munro <thomas.munro@gmail.com>; Simon Riggs <simon@2ndquadrant.com>; +Cc: pgsql-docs@lists.postgresql.org
On 2020/05/28 8:43, Thomas Munro wrote:
> On Wed, May 27, 2020 at 7:09 PM Simon Riggs <simon@2ndquadrant.com> wrote:
>> On Wed, 27 May 2020 at 04:27, Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
>>>
>>> Hi,
>>>
>>> The group of wal_init_zero and wal_recycle is WAL_SETTINGS in guc.c,
>>> but their descriptions are located in "19.6. Replication"/"19.6.1. Sending
>>> Servers" section. This seems a documentation bug. They should be located
>>> in "19.5. Write Ahead Log"/"19.5.1. Settings". Thought?
>>
>>
>> +1
Thanks! Patch attached.
Since they are located just before wal_buffers in postgresql.conf.sample,
I moved the descriptions of them also just before that of wal_buffers
in "Write Ahead Log"/"Settings" section.
BTW, while reading guc.c, I found the GUC context of wal_recycle is
PGC_SUSET. But isn't it better to set it to PGC_SIGHUP because wal_recycle
doesn't affect any backends? Basically checkpointer and startup process
use wal_recycle.
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
Attachments:
wal_guc_docs.patch (text/plain, 3.8K) download
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index a2694e548a..862baae0c8 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2820,6 +2820,41 @@ include_dir 'conf.d'
</listitem>
</varlistentry>
+ <varlistentry id="guc-wal-init-zero" xreflabel="wal_init_zero">
+ <term><varname>wal_init_zero</varname> (<type>boolean</type>)
+ <indexterm>
+ <primary><varname>wal_init_zero</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ If set to <literal>on</literal> (the default), this option causes new
+ WAL files to be filled with zeroes. On some file systems, this ensures
+ that space is allocated before we need to write WAL records. However,
+ <firstterm>Copy-On-Write</firstterm> (COW) file systems may not benefit
+ from this technique, so the option is given to skip the unnecessary
+ work. If set to <literal>off</literal>, only the final byte is written
+ when the file is created so that it has the expected size.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry id="guc-wal-recycle" xreflabel="wal_recycle">
+ <term><varname>wal_recycle</varname> (<type>boolean</type>)
+ <indexterm>
+ <primary><varname>wal_recycle</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ If set to <literal>on</literal> (the default), this option causes WAL
+ files to be recycled by renaming them, avoiding the need to create new
+ ones. On COW file systems, it may be faster to create new ones, so the
+ option is given to disable this behavior.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-wal-buffers" xreflabel="wal_buffers">
<term><varname>wal_buffers</varname> (<type>integer</type>)
<indexterm>
@@ -3752,41 +3787,6 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</listitem>
</varlistentry>
- <varlistentry id="guc-wal-init-zero" xreflabel="wal_init_zero">
- <term><varname>wal_init_zero</varname> (<type>boolean</type>)
- <indexterm>
- <primary><varname>wal_init_zero</varname> configuration parameter</primary>
- </indexterm>
- </term>
- <listitem>
- <para>
- If set to <literal>on</literal> (the default), this option causes new
- WAL files to be filled with zeroes. On some file systems, this ensures
- that space is allocated before we need to write WAL records. However,
- <firstterm>Copy-On-Write</firstterm> (COW) file systems may not benefit
- from this technique, so the option is given to skip the unnecessary
- work. If set to <literal>off</literal>, only the final byte is written
- when the file is created so that it has the expected size.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry id="guc-wal-recycle" xreflabel="wal_recycle">
- <term><varname>wal_recycle</varname> (<type>boolean</type>)
- <indexterm>
- <primary><varname>wal_recycle</varname> configuration parameter</primary>
- </indexterm>
- </term>
- <listitem>
- <para>
- If set to <literal>on</literal> (the default), this option causes WAL
- files to be recycled by renaming them, avoiding the need to create new
- ones. On COW file systems, it may be faster to create new ones, so the
- option is given to disable this behavior.
- </para>
- </listitem>
- </varlistentry>
-
<varlistentry id="guc-max-slot-wal-keep-size" xreflabel="max_slot_wal_keep_size">
<term><varname>max_slot_wal_keep_size</varname> (<type>integer</type>)
<indexterm>
* Re: wal_init_zero and wal_recycle
2020-05-27 03:27 wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
2020-05-27 07:08 ` Re: wal_init_zero and wal_recycle Simon Riggs <simon@2ndquadrant.com>
2020-05-27 23:43 ` Re: wal_init_zero and wal_recycle Thomas Munro <thomas.munro@gmail.com>
2020-05-29 04:13 ` Re: wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2020-06-02 05:25 ` Fujii Masao <masao.fujii@oss.nttdata.com>
2020-06-03 01:16 ` Re: wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
0 siblings, 1 reply; 6+ messages in thread
From: Fujii Masao @ 2020-06-02 05:25 UTC (permalink / raw)
To: Thomas Munro <thomas.munro@gmail.com>; Simon Riggs <simon@2ndquadrant.com>; +Cc: pgsql-docs@lists.postgresql.org
On 2020/05/29 13:13, Fujii Masao wrote:
>
>
> On 2020/05/28 8:43, Thomas Munro wrote:
>> On Wed, May 27, 2020 at 7:09 PM Simon Riggs <simon@2ndquadrant.com> wrote:
>>> On Wed, 27 May 2020 at 04:27, Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> The group of wal_init_zero and wal_recycle is WAL_SETTINGS in guc.c,
>>>> but their descriptions are located in "19.6. Replication"/"19.6.1. Sending
>>>> Servers" section. This seems a documentation bug. They should be located
>>>> in "19.5. Write Ahead Log"/"19.5.1. Settings". Thought?
>>>
>>>
>>> +1
>
> Thanks! Patch attached.
> Since they are located just before wal_buffers in postgresql.conf.sample,
> I moved the descriptions of them also just before that of wal_buffers
> in "Write Ahead Log"/"Settings" section.
Barring any objection, I will commit this patch.
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
^ permalink raw reply [nested|flat] 6+ messages in thread
* Re: wal_init_zero and wal_recycle
2020-05-27 03:27 wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
2020-05-27 07:08 ` Re: wal_init_zero and wal_recycle Simon Riggs <simon@2ndquadrant.com>
2020-05-27 23:43 ` Re: wal_init_zero and wal_recycle Thomas Munro <thomas.munro@gmail.com>
2020-05-29 04:13 ` Re: wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
2020-06-02 05:25 ` Re: wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
@ 2020-06-03 01:16 ` Fujii Masao <masao.fujii@oss.nttdata.com>
0 siblings, 0 replies; 6+ messages in thread
From: Fujii Masao @ 2020-06-03 01:16 UTC (permalink / raw)
To: Thomas Munro <thomas.munro@gmail.com>; Simon Riggs <simon@2ndquadrant.com>; +Cc: pgsql-docs@lists.postgresql.org
On 2020/06/02 14:25, Fujii Masao wrote:
>
>
> On 2020/05/29 13:13, Fujii Masao wrote:
>>
>>
>> On 2020/05/28 8:43, Thomas Munro wrote:
>>> On Wed, May 27, 2020 at 7:09 PM Simon Riggs <simon@2ndquadrant.com> wrote:
>>>> On Wed, 27 May 2020 at 04:27, Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> The group of wal_init_zero and wal_recycle is WAL_SETTINGS in guc.c,
>>>>> but their descriptions are located in "19.6. Replication"/"19.6.1. Sending
>>>>> Servers" section. This seems a documentation bug. They should be located
>>>>> in "19.5. Write Ahead Log"/"19.5.1. Settings". Thought?
>>>>
>>>>
>>>> +1
>>
>> Thanks! Patch attached.
>> Since they are located just before wal_buffers in postgresql.conf.sample,
>> I moved the descriptions of them also just before that of wal_buffers
>> in "Write Ahead Log"/"Settings" section.
>
> Barring any objection, I will commit this patch.
Pushed. Thanks!
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
^ permalink raw reply [nested|flat] 6+ messages in thread
end of thread, other threads:[~2020-06-03 01:16 UTC | newest]
Thread overview: 6+ messages (download: mbox mbox.gz follow: Atom feed)
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2020-05-27 03:27 wal_init_zero and wal_recycle Fujii Masao <masao.fujii@oss.nttdata.com>
2020-05-27 07:08 ` Simon Riggs <simon@2ndquadrant.com>
2020-05-27 23:43 ` Thomas Munro <thomas.munro@gmail.com>
2020-05-29 04:13 ` Fujii Masao <masao.fujii@oss.nttdata.com>
2020-06-02 05:25 ` Fujii Masao <masao.fujii@oss.nttdata.com>
2020-06-03 01:16 ` Fujii Masao <masao.fujii@oss.nttdata.com>
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