On Tue, May 12, 2020 at 03:38:16PM -0700, David G. Johnston wrote: > On Tue, May 12, 2020 at 2:41 PM Bruce Momjian <br...@momjian.us> wrote: > > On Tue, May 12, 2020 at 05:40:14PM -0400, Bruce Momjian wrote: > > On Tue, May 12, 2020 at 10:26:27AM +0000, PG Doc comments form wrote: > > > The following documentation comment has been logged on the website: > > > > > > Page: > https://www.postgresql.org/docs/11/runtime-config-autovacuum.html > > > Description: > > > > > > The `autovacuum_vacuum_cost_delay` setting changes to 2ms in > PostgreSQL > 12 > > > but in the old Postgresql version, the default setting is still 20ms. > I > > > would suggest adding a suggestion in the old document > > > to lower the autovacuum_vacuum_cost_delay as: > > > > > > > The default value of autovacuum_vacuum_cost_delay is reduced to 2ms > in > > > PostgreSQL 12. Reducing the autovacuum_vacuum_cost_delay will make the > > > autovacuum more aggressive and might reduce the vacuum cost for > > > write-intensive workload on big table. > > > > Uh, we usually don't suggest new defaults in back branches. > > Basically, what I am saying is that if you want this, it would be a new > behavior that would need general discussion. > > > > The proposal is to document in versions 9.4 to 11 that the recommended value > for the setting is 2ms while for reasons of continuity the default in these > versions is 20ms. > > I don't really see any harm in it. Its not like the choice to reduce the > value > was made because of new features introduced in 12 - it was a re-evaluation of > a > 15 year old default.
Well, we really need to have some general discussion about whether changing defaults in major releases should trigger a mention to change the defaults in back branches. This is something that would have to be discussed on the hackers list. -- Bruce Momjian <br...@momjian.us> https://momjian.us EnterpriseDB https://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription +
