Re: autovacuum

On Wed, Oct 29, 2008 at 4:46 PM, Matthew T. O'Connor <matthew(at)zeut(dot)net>wrote:

> Noah Freire wrote:
>
>> <2008-10-29 11:09:03.453 PDT>DEBUG: 00000: accounts: vac: 16697969
>> (threshold 6000050), anl: 16697969 (threshold 120000048)
>> <2008-10-29 11:09:05.610 PDT>DEBUG: 00000: accounts: vac: 16699578
>> (threshold 6000050), anl: 16699578 (threshold 120000048)
>> <2008-10-29 11:10:03.563 PDT>DEBUG: 00000: accounts: vac: 16735906
>> (threshold 6000050), anl: 16735906 (threshold 120000048)
>>
>> please check the first log message: the vacuum threshold is 6,000,050 rows
>> and the number of dead tuples is 16,697,969. Even though the number of
>> dead_tuples is greater than the threshold the autovacuum is not being
>> triggered for this table. So, besides this condition (dead_tuples >
>> threshold) what else is taken into account by autovacuum?
>>
>
> What version of PostgreSQL?

8.3

> Is the table being excluded? (see the pg_autovacuum system table settings)

there's an entry for this table on pg_autovacuum, and it's enabled.

> Are you sure that it's not getting processed? Perhaps one worker is / has
> been churning on this table for a *LONG* time (that is a fairly big
> table).

Right. I was wrong :-) the table is being processed by autovacuum (I checked
via pg_stat_activity). However, as you pinpointed, it's already running for
hours (the test workload ended hours ago, basically it is just this
autovacuum worker running on the system).

Is there a way to make a more aggressive autovacuum setting for this table?
it does not matter if it will affect performance, my concern is that it
finishes as soon as possible. I wonder if a manual vacuum wouldn't be
faster.

Thanks,

-Noah