Re: Problems with autovacuum

Tom Lane escribió:
> Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> > Tom Lane escribi:
> >> I believe the interpretation of autovacuum_naptime is that it should
> >> examine each database that often, ie once a minute by default. So
> >> it's got more than 30 databases per second to look through.
>
> > Note that this is correct in 8.1 and 8.2 but not 8.3 onwards.
>
> Oh? The current documentation still defines the variable thusly:
>
> Specifies the minimum delay between autovacuum runs on any given
> database. In each round the daemon examines the database and
> issues VACUUM and ANALYZE commands as needed for tables in that
> database.

Sorry, it's the other way around actually -- correct for 8.3 onwards,
wrong for 8.1 and 8.2. In the earlier versions, it would do one run in
a chosen database, sleep during "naptime", then do another run.

> I suppose the use of "minimum" means that this is not technically
> incorrect, but it's sure not very helpful if there is some other
> rule involved that causes it to not behave as I said. (And if there
> is some other rule, what is that?)

The word "minimum" is there because it's possible that all workers are
busy with some other database(s).

> Please improve the docs.

I'll see about that.

--
Alvaro Herrera http://www.CommandPrompt.com/
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