Josh Berkus escribió:
> #autovacuum_vacuum_scale_factor = 0.2
>
> This is set because in my experience, 20% bloat is about the level at
> which bloat starts affecting performance; thus, we want to vacuum at
> that level but not sooner. This does mean that very large tables which
> never have more than 10% updates/deletes don't get vacuumed at all until
> freeze_age; this is a *good thing*. VACUUM on large tables is expensive;
> you don't *want* to vacuum a billion-row table which has only 100,000
> updates.
Hmm, now that we have partial vacuum, perhaps we should revisit this.
> It would be worth doing a DBT2/DBT5 test run with different autovac
> settings post-8.4 so see if we should specifically change the vacuum
> threshold.
Right.
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
