Hi,
On Thu, Apr 2, 2015 at 12:47 PM, Pietro Pugni <pietro.pugni@gmail.com> wrote:
> Hi Jeff,
> thank you for your response.
> I’m using Postgres 9.0 on MacMini because I’ve noticed that it’s quite fast
> compared to different Ubuntu machines on which I’ve worked with different
> (and more performant) hardware.
> The built-in Postgres version on OS X Server is impossible to update. I
> should stop it and install a parallel and independent distribution which has
> not been optimized by Apple. On opensource.appel.com they have different
> Postgres versions but the latest one is 9.2.x. They stopped updating it in
> 2012.
If you want you can compile 9.0 on OSX and double check.
I don't remember well but ITSM that a fsync used by psql was a noop on OSX.
> pg_test_fsync tells me that T420 disk iops are ~7 times faster than MacMini,
> which is ok, but queries run ~2-5 times slower (for brevity I didn’t report
> all test results in my first mail).
>
> I’ve searched just now what a collation is because I’ve never explicitly
> used one before, so I think it uses the default one.
What's the output of free and sysctl -a | grep vm.zone_reclaim_mode
Search the mailing list for zone_reclaim_mode there's some tips.
For testing you can also use the mac mini config with the dell, at
least it should give you the same plan.
With your example disks don't seem to matter, it's all in memory.
Keep in mind that a psql query is still single thread so the mac and
the dell should get more or less the same speed for in memory queries.
>
> B_2 query is of the form:
> WITH soggetti AS (
> SELECT ... FROM ... GROUP BY ...)
> SELECT ... INTO ... FROM soggetti, ... WHERE ...
>
> (I omit the … part because they’re not relevant)
>
> Best regards,
> Pietro
