pg.ddx.io pgsql-docs@postgresql.org mailing list archive
help / color / mirror / Atom feedbgwriter_lru_multiplier maximum value
5+ messages / 4 participants
[nested] [flat]
* bgwriter_lru_multiplier maximum value
@ 2019-04-01 10:27 PG Doc comments form <noreply@postgresql.org>
0 siblings, 1 reply; 5+ messages in thread
From: PG Doc comments form @ 2019-04-01 10:27 UTC (permalink / raw)
To: pgsql-docs@lists.postgresql.org; +Cc: chris+postgresql@qwirx.com
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/11/runtime-config-resource.html
Description:
The server has an undocumented maximum value of 10 for
bgwriter_lru_multiplier, and will fail to start if it's set higher than
this:
LOG: 20 is outside the valid range for parameter "bgwriter_lru_multiplier"
(0 .. 10)
FATAL: configuration file "/.../pgdata/postgresql.conf" contains errors
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: bgwriter_lru_multiplier maximum value
@ 2019-04-01 13:18 Michael Paquier <michael@paquier.xyz>
parent: PG Doc comments form <noreply@postgresql.org>
0 siblings, 1 reply; 5+ messages in thread
From: Michael Paquier @ 2019-04-01 13:18 UTC (permalink / raw)
To: chris+postgresql@qwirx.com; pgsql-docs@lists.postgresql.org
On Mon, Apr 01, 2019 at 10:27:13AM +0000, PG Doc comments form wrote:
> The server has an undocumented maximum value of 10 for
> bgwriter_lru_multiplier, and will fail to start if it's set higher than
> this:
>
> LOG: 20 is outside the valid range for parameter "bgwriter_lru_multiplier"
> (0 .. 10)
> FATAL: configuration file "/.../pgdata/postgresql.conf" contains errors
I would suggest something like that:
inline patch 1: doc/src/sgml/config.sgml (+2/-1 lines) download inline-1.patch
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2050,7 +2050,8 @@ include_dir 'conf.d'
Larger values provide some cushion against spikes in demand,
while smaller values intentionally leave writes to be done by
server processes.
- The default is 2.0.
+ The default is 2.0. The value can range from <literal>2.0</literal>
+ to <literal>10.0</literal>
This parameter can only be set in the <filename>postgresql.conf</filename>
file or on the server command line.
</para>
* Re: bgwriter_lru_multiplier maximum value
@ 2019-04-01 13:22 Tom Lane <tgl@sss.pgh.pa.us>
parent: Michael Paquier <michael@paquier.xyz>
0 siblings, 1 reply; 5+ messages in thread
From: Tom Lane @ 2019-04-01 13:22 UTC (permalink / raw)
To: Michael Paquier <michael@paquier.xyz>; +Cc: chris+postgresql@qwirx.com; pgsql-docs@lists.postgresql.org
Michael Paquier <michael@paquier.xyz> writes:
> On Mon, Apr 01, 2019 at 10:27:13AM +0000, PG Doc comments form wrote:
>> The server has an undocumented maximum value of 10 for
>> bgwriter_lru_multiplier, and will fail to start if it's set higher than
>> this:
> Any opinions from others?
I don't think it's generally our practice to specify min and max
values in config.sgml. If we were to start doing so, we'd need
a much bigger patch than this, and it'd be an ongoing maintenance
issue.
Unless there's some reason I'm missing why the limits are more
significant for this variable than for others?
regards, tom lane
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: bgwriter_lru_multiplier maximum value
@ 2019-04-01 14:09 Chris Wilson <chris+postgresql@qwirx.com>
parent: Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 1 reply; 5+ messages in thread
From: Chris Wilson @ 2019-04-01 14:09 UTC (permalink / raw)
To: Tom Lane <tgl@sss.pgh.pa.us>; +Cc: Michael Paquier <michael@paquier.xyz>; pgsql-docs@lists.postgresql.org
Hi all,
We do document the range for some parameters:
- bgwriter_flush_after: "The valid range is between 0, which disables
forced writeback, and 2MB."
- effective_io_concurrency (integer): "The allowed range is 1 to 1000,
or zero to disable issuance of asynchronous I/O requests."
- backend_flush_after (integer): "The valid range is between 0, which
disables forced writeback, and 2MB."
My argument for documenting this one would extend to all parameters that
can only be set at server startup time, and for which exceeding the maximum
(or minimum) value would cause the server to fail to start. In these cases
the change cannot be tested without risk of downtime. It's also not clear
where to look (e..g in the code) for the limits on allowed range.
+ The default is 2.0. The value can range from
> <literal>2.0</literal>
If we are going to change it, the minimum value is apparently 0, not 2.
Thanks, Chris.
On Mon, 1 Apr 2019 at 14:23, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Michael Paquier <michael@paquier.xyz> writes:
> > On Mon, Apr 01, 2019 at 10:27:13AM +0000, PG Doc comments form wrote:
> >> The server has an undocumented maximum value of 10 for
> >> bgwriter_lru_multiplier, and will fail to start if it's set higher than
> >> this:
>
> > Any opinions from others?
>
> I don't think it's generally our practice to specify min and max
> values in config.sgml. If we were to start doing so, we'd need
> a much bigger patch than this, and it'd be an ongoing maintenance
> issue.
>
> Unless there's some reason I'm missing why the limits are more
> significant for this variable than for others?
>
> regards, tom lane
>
^ permalink raw reply [nested|flat] 5+ messages in thread
* Re: bgwriter_lru_multiplier maximum value
@ 2019-04-02 01:52 Michael Paquier <michael@paquier.xyz>
parent: Chris Wilson <chris+postgresql@qwirx.com>
0 siblings, 0 replies; 5+ messages in thread
From: Michael Paquier @ 2019-04-02 01:52 UTC (permalink / raw)
To: Chris Wilson <chris+postgresql@qwirx.com>; +Cc: Tom Lane <tgl@sss.pgh.pa.us>; pgsql-docs@lists.postgresql.org
On Mon, Apr 01, 2019 at 03:09:39PM +0100, Chris Wilson wrote:
> If we are going to change it, the minimum value is apparently 0, not
> 2.
Ditto. I misread guc.c.
--
Michael
Attachments:
signature.asc (application/pgp-signature, 832B) download
^ permalink raw reply [nested|flat] 5+ messages in thread
end of thread, other threads:[~2019-04-02 01:52 UTC | newest]
Thread overview: 5+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2019-04-01 10:27 bgwriter_lru_multiplier maximum value PG Doc comments form <noreply@postgresql.org>
2019-04-01 13:18 ` Michael Paquier <michael@paquier.xyz>
2019-04-01 13:22 ` Tom Lane <tgl@sss.pgh.pa.us>
2019-04-01 14:09 ` Chris Wilson <chris+postgresql@qwirx.com>
2019-04-02 01:52 ` Michael Paquier <michael@paquier.xyz>
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox