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wal_compression = on: what is the algorithm?
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* wal_compression = on: what is the algorithm?
@ 2024-11-15 15:30 PG Doc comments form <noreply@postgresql.org>
  2024-11-20 16:22 ` Re: wal_compression = on: what is the algorithm? Bruce Momjian <bruce@momjian.us>
  0 siblings, 1 reply; 3+ messages in thread

From: PG Doc comments form @ 2024-11-15 15:30 UTC (permalink / raw)
  To: pgsql-docs@lists.postgresql.org; +Cc: christophe.courtois@dalibo.com

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/16/runtime-config-wal.html
Description:

In
https://www.postgresql.org/docs/16/runtime-config-wal.html#GUC-WAL-COMPRESSION,
the option "on" is not described:

“The supported methods are pglz, lz4 (if PostgreSQL was compiled with
--with-lz4) and zstd (if PostgreSQL was compiled with --with-zstd). The
default value is off. ”

"on" was an available option before PG 15, and still seen in some docs.
If I understand the code in src/backend/utils/misc/guc_tables.c, "on" is the
same as "pglz". So I suggest:

“The supported methods are pglz, lz4 (if PostgreSQL was compiled with
--with-lz4) and zstd (if PostgreSQL was compiled with --with-zstd). The
default value is off.  The value on is synonym of pglz.”

I didn't see this discussed in
https://www.postgresql.org/message-id/flat/3037310D-ECB7-4BF1-AF20-01C10BB33A33%40yandex-team.ru


^ permalink  raw  reply  [nested|flat] 3+ messages in thread

* Re: wal_compression = on: what is the algorithm?
  2024-11-15 15:30 wal_compression = on: what is the algorithm? PG Doc comments form <noreply@postgresql.org>
@ 2024-11-20 16:22 ` Bruce Momjian <bruce@momjian.us>
  2024-11-21 01:12   ` Re: wal_compression = on: what is the algorithm? Michael Paquier <michael@paquier.xyz>
  0 siblings, 1 reply; 3+ messages in thread

From: Bruce Momjian @ 2024-11-20 16:22 UTC (permalink / raw)
  To: christophe.courtois@dalibo.com; pgsql-docs@lists.postgresql.org

On Fri, Nov 15, 2024 at 03:30:59PM +0000, PG Doc comments form wrote:
> The following documentation comment has been logged on the website:
> 
> Page: https://www.postgresql.org/docs/16/runtime-config-wal.html
> Description:
> 
> In
> https://www.postgresql.org/docs/16/runtime-config-wal.html#GUC-WAL-COMPRESSION,
> the option "on" is not described:
> 
> “The supported methods are pglz, lz4 (if PostgreSQL was compiled with
> --with-lz4) and zstd (if PostgreSQL was compiled with --with-zstd). The
> default value is off. ”
> 
> "on" was an available option before PG 15, and still seen in some docs.
> If I understand the code in src/backend/utils/misc/guc_tables.c, "on" is the
> same as "pglz". So I suggest:
> 
> “The supported methods are pglz, lz4 (if PostgreSQL was compiled with
> --with-lz4) and zstd (if PostgreSQL was compiled with --with-zstd). The
> default value is off.  The value on is synonym of pglz.”

I think we kept 'on' just for backward compatibility, so we don't
mention it in the docs anymore.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  When a patient asks the doctor, "Am I going to die?", he means 
  "Am I going to die soon?"





^ permalink  raw  reply  [nested|flat] 3+ messages in thread

* Re: wal_compression = on: what is the algorithm?
  2024-11-15 15:30 wal_compression = on: what is the algorithm? PG Doc comments form <noreply@postgresql.org>
  2024-11-20 16:22 ` Re: wal_compression = on: what is the algorithm? Bruce Momjian <bruce@momjian.us>
@ 2024-11-21 01:12   ` Michael Paquier <michael@paquier.xyz>
  0 siblings, 0 replies; 3+ messages in thread

From: Michael Paquier @ 2024-11-21 01:12 UTC (permalink / raw)
  To: Bruce Momjian <bruce@momjian.us>; +Cc: christophe.courtois@dalibo.com; pgsql-docs@lists.postgresql.org

On Wed, Nov 20, 2024 at 11:22:51AM -0500, Bruce Momjian wrote:
> I think we kept 'on' just for backward compatibility, so we don't
> mention it in the docs anymore.

True, but we show it based on wal_compression_options and list it in
postgresql.conf.sample.  So we could as well add this extra line about
"on" matching with pglz knowing that the docs mention "off".
Christophe's suggestion sounds like a good thing, IMO.
--
Michael

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^ permalink  raw  reply  [nested|flat] 3+ messages in thread


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2024-11-20 16:22 ` Bruce Momjian <bruce@momjian.us>
2024-11-21 01:12   ` Michael Paquier <michael@paquier.xyz>

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