Re: Tuning on server with both running oracle and postgreSQL database

On Wed, Jul 1, 2015 at 3:00 PM, koff10 <koff10(at)hotmail(dot)com> wrote:
>
> Hi all,
> Is there anyone experienced in memory management about server running
> oracle and postgres database ?
> I have server running on Redhat 6.4 with 64 Go of physical memory.
>
> I want to install Postgresql onto a "production" server
> that currently runs Oracle. Are there any problems with running Postgresql
> and Oracle on the same machine.
>
> Anything special to know about memory, SHMMAX,SHMALL ,disk layout, and
> things like that?
> thanks

How hard are each db engine going to be working? If postgresql just
needs to store a few thousand rows then no tuning is needed. If both
work as hard as each other, then you'll need to "steal" some memory
from Oracle to let postgresql run well.

Will Oracle be doing most of the work?

Are you planning a migration from Oracle to PostgreSQL and this is a
temporary thing?

Prior to 9.4 you'll have to worry about shmmax/shmmall and making sure
they're big enough for the shared_buffers you want pgsql to have. 1G
is usually plenty for most uses.

Keep postgresql's work_mem smallish esp if you're gonna have a lot of
connections to it. Use connection pooling if you're gonna have more
than a few dozen connections to postgresql.

But the big question is, what's your usage planned to look like? That
guides a LOT of decisions here.