Jim C. Nasby escribió:
> There *is* reason to allow setting the naptime smaller, though (or at
> least there was; perhaps Alvero's recent changes negate this need):
> clusters that have a large number of databases. I've worked with folks
> who are in a hosted environment and give each customer their own
> database; it's not hard to get a couple hundred databases that way.
> Setting the naptime higher than a second in such an environment would
> mean it could be hours before a database is checked for vacuuming.
Yes, the code in HEAD is different -- each database will be considered
separately. So the huge database taking all day to vacuum will not stop
the tiny databases from being vacuumed in a timely manner.
And the very huge table in that database will not stop the other tables
in the database from being vacuumed either. There can be more than one
worker in a single database.
The limit is autovacuum_max_workers.
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.