Alvaro Herrera wrote:
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.
Ok, but I think the question posed is that in say a virtual hosting
environment there might be say 1,000 databases in the cluster. Am I
still going to have to wait a long time for my database to get vacuumed?
I don't think this has changed much no?
(If default naptime is 1 minute, then autovacuum won't even look at a
given database but once every 1,000 minutes (16.67 hours) assuming that
there isn't enough work to keep all the workers busy.)
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