Re: Vacuum, Freeze and Analyze: the big picture

On 2013-05-30 12:11:23 -0700, Josh Berkus wrote:
> 
> > Inhowfar did 8.4 make freezing worse? I can't remember any new problems
> > there?
> 
> Before the Visibility Map, we always vacuumed all pages in a relation
> when it was vacuumed at all.  This means that we froze tuples at
> vacuum_min_freeze_age, not at autovacuum_max_freeze_age, which is when
> we do it post-8.4.

If we have reason to vacuum the relation we do it at
vacuum_freeze_table_age, not only at autovacuum_max_freeze_age. The
difference is that the latter triggers a vacuum, while the former only
changes a partial vacuum into a full one.

Calling that behaviour unconditionally worse is, err, interesting...

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
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