Re: Unable to test parallel aggregate/joins in Postgres beta 2

On Thu, Jul 14, 2016 at 6:59 PM, Devrim Gündüz <devrim@gunduz.org> wrote:

Hi,

On Thu, 2016-07-14 at 18:46 +0530, Madusudanan.B.N wrote:
> I installed postgres beta 2 using the RPM provided here for Cent OS.
>
> Based on this article I was trying to set *max_parallel_degree*, but
> postgres complained that there was no such config variable. But I was able
> to set *max_parallel_workers_per_gather* and test things for parallel
> sequential scan

That article seems to be pre-beta2. The name of the parameter was changed to
max_parallel_workers_per_gather, so what you did was correct.

> I have a hunch that I have installed a previous beta version i.e beta 1,
> but *Select version()* reported that I was using 9.6beta2 only.

What makes you feel like you have beta1 installed? Can I get the output of:

rpm -qa|grep postgresql

My bad, the installation is correct, it reports the following version numbers as expected.

postgresql96-contrib-9.6beta2-2PGDG.rhel6.x86_64
postgresql96-9.6beta2-2PGDG.rhel6.x86_64
postgresql96-libs-9.6beta2-2PGDG.rhel6.x86_64
postgresql96-server-9.6beta2-2PGDG.rhel6.x86_64

I though that since parallel sequential scan was committed earlier and in my testing parallelism was working correctly, perhaps I was testing in an earlier version.

But the reason why it did not chose a parallel plan was because of an order by clause without an index. Does pg support parallel sort ? This was in the dev pipeline but not sure whether the work is done already.

Again, I am not completely sure that an order by clause is the reason, ill test more and get back.  

> What have I done wrong ?
>
> 1) The RPM file that I downloaded has 9.6 beta 1. Name is mentioned as
> pgdg-redhat96-9.6-1.noarch.rpm.

This is *not* PostgreSQL version -- this is the repository RPM only.

Thanks for that information. I'll keep that mind.

 

> 2) Should beta2 built only from source ? If the RPM is beta 1 why is the
> server version reporting as beta2 ?

See above.


Regards,

--
Devrim GÜNDÜZ
Principal Systems Engineer @ EnterpriseDB: http://www.enterprisedb.com
PostgreSQL Danışmanı/Consultant, Red Hat Certified Engineer
Twitter: @DevrimGunduz , @DevrimGunduzTR

--

Regards,
Madusudanan.B.N