Josh Berkus wrote:
> In terms of adding a new GUC in 9.5: can't we take a stab at auto-tuning
> this instead of adding a new GUC? We already have a bunch of freezing
> GUCs which fewer than 1% of our user base has any idea how to set.
If you have development resources to pour onto 9.5, I think it would be
better spent changing multixact usage tracking so that oldestOffset is
included in pg_control; also make pg_multixact truncation be WAL-logged.
With those changes, the need for a lot of pretty complicated code would
go away. The fact that truncation is done by both vacuum and checkpoint
causes a lot of the mess we were in (and from which Robert and Thomas
took us --- thanks guys!). Such a change is the first step towards
auto-tuning, I think.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
