vacuum_cost_limit doc description patch

Started by Martín Marquésabout 8 years ago4 messageshackers
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#1Martín Marqués
martin.marques@gmail.com

Hi,

Today looking for information on hard limits for
autovacuum_vacuum_cost_limit I found myself with a very short
description in the docs.

This is a patch to add some further description, plus the upper and
lower limits it has.

--
Martín Marqués
select 'martin.marques' || '@' || 'gmail.com'
DBA, Programador, Administrador

Attachments:

0001-Describe-better-vacuum_cost_limit-mentioning-the-low.patchtext/x-patch; charset=US-ASCII; name=0001-Describe-better-vacuum_cost_limit-mentioning-the-low.patchDownload+3-3
#2David Rowley
dgrowleyml@gmail.com
In reply to: Martín Marqués (#1)
Re: vacuum_cost_limit doc description patch

On 11 April 2018 at 09:13, Martín Marqués <martin.marques@gmail.com> wrote:

This is a patch to add some further description, plus the upper and
lower limits it has.

Hi,

+ for vacuum_cost_delay. The parameter can take a value
between 1 and 10000.

vacuum_cost_delay should be in <varname> tags.

+1 to mentioning that we sleep for vacuum_cost_delay, but I just don't
see many other GUCs with mention of their supported range.

effective_io_concurrency mentions the range it supports, but this
happens to depend on USE_POSIX_FADVISE, which if undefined the maximum
setting is 0, which means the docs are wrong in some cases on that.

vacuum_cost_limit seems fairly fixed at 0-10000 with no compile-time
conditions, so perhaps it's okay, providing we remember and update the
docs if that ever changes.

--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

#3Martin Marques
martin.marques@2ndquadrant.com
In reply to: David Rowley (#2)
Re: vacuum_cost_limit doc description patch

El 11/04/18 a las 02:04, David Rowley escribió:

On 11 April 2018 at 09:13, Martín Marqués <martin.marques@gmail.com> wrote:

This is a patch to add some further description, plus the upper and
lower limits it has.

Hi,

+ for vacuum_cost_delay. The parameter can take a value
between 1 and 10000.

vacuum_cost_delay should be in <varname> tags.

+1 to mentioning that we sleep for vacuum_cost_delay, but I just don't
see many other GUCs with mention of their supported range.

Thanks David for having a look.

New version attached with the missing <varname> tags.

effective_io_concurrency mentions the range it supports, but this
happens to depend on USE_POSIX_FADVISE, which if undefined the maximum
setting is 0, which means the docs are wrong in some cases on that.

vacuum_cost_limit seems fairly fixed at 0-10000 with no compile-time
conditions, so perhaps it's okay, providing we remember and update the
docs if that ever changes.

I'm also adding a second patch over the config.sgml doc to fix what I
believe is a misguidance in the minimum resolution time modern systems have.

The patch just changes *many* for *some* systems which have a minimum
resolution time of 10 milliseconds.

--
Martín Marqués http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

Attachments:

0001-Describe-better-vacuum_cost_limit-mentioning-the-low.patchtext/x-patch; name=0001-Describe-better-vacuum_cost_limit-mentioning-the-low.patchDownload+3-3
0002-In-the-past-there-were-many-systems-which-which-had-.patchtext/x-patch; name=0002-In-the-past-there-were-many-systems-which-which-had-.patchDownload+2-3
#4Bruce Momjian
bruce@momjian.us
In reply to: Martin Marques (#3)
Re: vacuum_cost_limit doc description patch

On Fri, Apr 13, 2018 at 09:56:18AM -0300, Martín Marqués wrote:

El 11/04/18 a las 02:04, David Rowley escribió:

On 11 April 2018 at 09:13, Martín Marqués <martin.marques@gmail.com> wrote:

This is a patch to add some further description, plus the upper and
lower limits it has.

Hi,

+ for vacuum_cost_delay. The parameter can take a value
between 1 and 10000.

vacuum_cost_delay should be in <varname> tags.

+1 to mentioning that we sleep for vacuum_cost_delay, but I just don't
see many other GUCs with mention of their supported range.

Thanks David for having a look.

New version attached with the missing <varname> tags.

effective_io_concurrency mentions the range it supports, but this
happens to depend on USE_POSIX_FADVISE, which if undefined the maximum
setting is 0, which means the docs are wrong in some cases on that.

vacuum_cost_limit seems fairly fixed at 0-10000 with no compile-time
conditions, so perhaps it's okay, providing we remember and update the
docs if that ever changes.

I'm also adding a second patch over the config.sgml doc to fix what I
believe is a misguidance in the minimum resolution time modern systems have.

The patch just changes *many* for *some* systems which have a minimum
resolution time of 10 milliseconds.

Patch applied to master, though I removed the valid range part of the
patch. I also liked the many-to-some change since it is more accurate.

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

Only you can decide what is important to you.