Re: BUG #12834: Avoiding Disk Control Writes for better Laptop / SSD compatibility. pgstats

On Thu, Mar 5, 2015 at 11:44 AM, Alvaro Herrera <alvherre@2ndquadrant.com>
wrote:

> Bryce Nesbitt wrote:
> > Is autovac writing anything of import during its periodic wakeup on
> an idle cluster?
>
> Autovacuum is not writing anything....
> The issue is that the timestamp-of-last-update bit, which is critical to
> autovacuum, does not get written unless the whole file is.  I guess it
> is possible to optimize that, so that the file is not touched other than
> the timestamp if the database has been completely idle.


That all sounded really reasonable.    So I checked into turning off vac
for this particular laptop
and discovered:

/etc/postgresql/9.3/main/postgresql.conf
#autovacuum = on
#autovacuum_naptime = 1min

(At Ubuntu's default).  So autovacuum is *not the droid we're looking
for...*