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Incorrect description of autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor
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* Incorrect description of autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor
@ 2018-09-27 20:22  PG Doc comments form <[email protected]>
  0 siblings, 1 reply; 3+ messages in thread

From: PG Doc comments form @ 2018-09-27 20:22 UTC (permalink / raw)
  To: [email protected]; +Cc: [email protected]

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/10/static/runtime-config-autovacuum.html
Description:

This page lists the different autovacuum options. Describing
autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor independently
adds confusion unless you are also reading
https://www.postgresql.org/docs/10/static/routine-vacuuming.html#AUTOVACUUM
where we have a formula for the threshold and scale factor.

I suggest adding a reference for each one of the two parameters with a link
to the "Routine Vacuuming" section.


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

* Re: Incorrect description of autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor
@ 2018-09-27 21:05  Alvaro Herrera <[email protected]>
  parent: PG Doc comments form <[email protected]>
  0 siblings, 1 reply; 3+ messages in thread

From: Alvaro Herrera @ 2018-09-27 21:05 UTC (permalink / raw)
  To: [email protected]; [email protected]

On 2018-Sep-27, PG Doc comments form wrote:

> Page: https://www.postgresql.org/docs/10/static/runtime-config-autovacuum.html
> 
> This page lists the different autovacuum options. Describing
> autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor independently
> adds confusion unless you are also reading
> https://www.postgresql.org/docs/10/static/routine-vacuuming.html#AUTOVACUUM
> where we have a formula for the threshold and scale factor.

True.

> I suggest adding a reference for each one of the two parameters with a link
> to the "Routine Vacuuming" section.

I suggest adding "This number is added to the number coming from the
autovacuum_vacuum_scale_factor parameter for each table" just before the
"This parameter can only be set" phrase.  So we'd end up with this:

autovacuum_vacuum_threshold (integer)
Specifies the minimum number of updated or deleted tuples needed to trigger a VACUUM in any one table. The default is 50 tuples. This number is added to the number coming from the autovacuum_vacuum_scale_factor parameter for each table.  This parameter can only be set in the postgresql.conf file or on the server command line; but the setting can be overridden for individual tables by changing table storage parameters.

autovacuum_vacuum_scale_factor (floating point)
Specifies a fraction of the table size to add to autovacuum_vacuum_threshold when deciding whether to trigger a VACUUM. The default is 0.2 (20% of table size). This number is added to the autovacuum_vacuum_threshold parameter for each table.  This parameter can only be set in the postgresql.conf file or on the server command line; but the setting can be overridden for individual tables by changing table storage parameters.

Same for the analyze parameters.

I suppose we don't need any updates to the section of
https://www.postgresql.org/docs/10/static/sql-createtable.html that
explains the equivalent reloptions, since those ones are very succint
anyway.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services




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

* Re: Incorrect description of autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor
@ 2018-09-28 01:26  Martín Marqués <[email protected]>
  parent: Alvaro Herrera <[email protected]>
  0 siblings, 0 replies; 3+ messages in thread

From: Martín Marqués @ 2018-09-28 01:26 UTC (permalink / raw)
  To: Alvaro Herrera <[email protected]>; +Cc: [email protected]

El jue., 27 sept. 2018 a las 18:05, Alvaro Herrera
(<[email protected]>) escribió:
>
> I suggest adding "This number is added to the number coming from the
> autovacuum_vacuum_scale_factor parameter for each table" just before the
> "This parameter can only be set" phrase.  So we'd end up with this:
>
> autovacuum_vacuum_threshold (integer)
> Specifies the minimum number of updated or deleted tuples needed to trigger a VACUUM in any one table. The default is 50 tuples. This number is added to the number coming from the autovacuum_vacuum_scale_factor parameter for each table.  This parameter can only be set in the postgresql.conf file or on the server command line; but the setting can be overridden for individual tables by changing table storage parameters.
>
> autovacuum_vacuum_scale_factor (floating point)
> Specifies a fraction of the table size to add to autovacuum_vacuum_threshold when deciding whether to trigger a VACUUM. The default is 0.2 (20% of table size). This number is added to the autovacuum_vacuum_threshold parameter for each table.  This parameter can only be set in the postgresql.conf file or on the server command line; but the setting can be overridden for individual tables by changing table storage parameters.

That looks very good IMO.

--
Martín Marqués
It’s not that I have something to hide,
it’s that I have nothing I want you to see





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


end of thread, other threads:[~2018-09-28 01:26 UTC | newest]

Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2018-09-27 20:22 Incorrect description of autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor PG Doc comments form <[email protected]>
2018-09-27 21:05 ` Alvaro Herrera <[email protected]>
2018-09-28 01:26   ` Martín Marqués <[email protected]>

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