| From: | Bryce Nesbitt <bryce2(at)obviously(dot)com> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-bugs(at)postgresql(dot)org |
| Subject: | Re: BUG #12834: Avoiding Disk Control Writes for better Laptop / SSD compatibility. pgstats |
| Date: | 2015-03-06 02:10:51 |
| Message-ID: | CAC9LFPer9Nr3LOX4XtT3mSsSuGti90oHBaDLeV9dxo-HFguojA@mail.gmail.com |
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| Lists: | pgsql-bugs |
On Thu, Mar 5, 2015 at 11:44 AM, Alvaro Herrera <alvherre(at)2ndquadrant(dot)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...*
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