From: | Don Seiler <don(at)seiler(dot)us> |
---|---|
To: | Joe Conway <mail(at)joeconway(dot)com> |
Cc: | pgsql-admin <pgsql-admin(at)postgresql(dot)org> |
Subject: | Re: Why is my table not autovacuuming? |
Date: | 2017-08-28 16:12:58 |
Message-ID: | CAHJZqBDBYBoBRy1x-6-Y5NNcNaM6LKsjDD0bE8ewik3U+bev6g@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-admin |
Same concerns as Phil's reply. Are the numbers in pg_stat_all_tables not
part of what autovacuum looks at? I assume those numbers would be updated
by autoanalyze but if that only kicks in at 10% scale factor then that
wouldn't happen for a while either? Seems like there's a huge disconnect
here, or I just don't have my head around this properly. Or both.
Don.
On Mon, Aug 28, 2017 at 10:59 AM, Joe Conway <mail(at)joeconway(dot)com> wrote:
> On 08/28/2017 08:43 AM, Don Seiler wrote:
> > PostgreSQL 9.2.18. I have a table with 71M rows (via select count). In
> > pg_stat_activity, n_live_tups is 170K, n_dead_tups is slightly more than
> > that (203K). The autovacuum parameter is on, the scale factor is 0.2
> > (default) and threshold is 50 (default), autovacuum_max_workers is 3.
> > There are no custom autovacuum thresholds set for this table. The
> > last_autovacuum field is null.
>
> <snip>
>
> > Wondering why my autovacuum daemon appears to be acting lazily?
>
> Autovac will kick in at (threshold + (scale_factor x 71M)), i.e. about
> 14.2 million dead rows. You are currently nowhere close to that.
>
> That said, the default scale_factor is not good to such a large table.
> Reduce it significantly. I often will find it necessary to use custom
> values for large tables. One strategy I have used is scale_factor = 0
> and threshold = <num_dead_rows_max_desired>.
>
> Joe
>
> --
> Crunchy Data - http://crunchydata.com
> PostgreSQL Support for Secure Enterprises
> Consulting, Training, & Open Source Development
>
>
--
Don Seiler
www.seiler.us
From | Date | Subject | |
---|---|---|---|
Next Message | Joe Conway | 2017-08-28 16:13:03 | Re: Why is my table not autovacuuming? |
Previous Message | Joe Conway | 2017-08-28 15:59:37 | Re: Why is my table not autovacuuming? |