Thread: Incorrect description of autovacuum_vacuum_threshold andautovacuum_vacuum_scale_factor
Incorrect description of autovacuum_vacuum_threshold andautovacuum_vacuum_scale_factor
From
PG Doc comments form
Date:
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.
Re: Incorrect description of autovacuum_vacuum_threshold andautovacuum_vacuum_scale_factor
From
Alvaro Herrera
Date:
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 50tuples. This number is added to the number coming from the autovacuum_vacuum_scale_factor parameter for each table. Thisparameter can only be set in the postgresql.conf file or on the server command line; but the setting can be overriddenfor 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. Thedefault 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 overriddenfor 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
Re: Incorrect description of autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor
From
Martín Marqués
Date:
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 50tuples. This number is added to the number coming from the autovacuum_vacuum_scale_factor parameter for each table. Thisparameter can only be set in the postgresql.conf file or on the server command line; but the setting can be overriddenfor 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 eachtable. This parameter can only be set in the postgresql.conf file or on the server command line; but the setting canbe 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