On 10/21/2016 10:29 AM, Robert Haas wrote: > On Fri, Oct 21, 2016 at 1:17 PM, Josh Berkus <j...@agliodbs.com> wrote: >> Particularly, with 9.6's freeze map, point (2) is even stronger reason >> to *lower* autovacuum_max_freeze_age. Since there's little duplicate >> work in a freeze scan, a lot of users will find that frequent freezing >> benefits them a lot ... > > That's a very good point, although I hope that vacuum is mostly being > triggered by vacuum_freeze_table_age rather than > autovacuum_freeze_max_age.
Well, depends on the nature of writes to the table. For insert-mostly tables, vacuum_freeze_table_age is pretty much never triggered. Isn't there a patch for that somewhere? > > On Bruce's original question, there is an answer written into our > documentation: "Vacuum also allows removal of old files from the > pg_clog subdirectory, which is why the default is a relatively low 200 > million transactions." Point. -- -- Josh Berkus Red Hat OSAS (any opinions are my own) -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
