Incorrect description of autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor
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.
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.
--
�lvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
El jue., 27 sept. 2018 a las 18:05, Alvaro Herrera
(<alvherre@2ndquadrant.com>) 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