Re: 2 instances of postmaster with different data directories

surabhi.ahuja wrote:
> Hi,
>
> I am going to integrate my dtabase into a system. That system also
> has another database and uses postgres.
>
> However they have their own data directory and start postmaster by
> specifying that.
>
> I have seen that it is possible to run multiple postmasters on
> multiple ports by specifying diffrent data directories.
>
> But we are still to decide if we should go with the above
> approach....or is it better to have just one data directory and one
> instance of postmaster on the default port.

Two instances will be less efficient:
- two separate areas of shared-memory
- two caches
- possible I/O competition (particularly with WAL I'd expect)
- twice as many upgrades needed when patches are released
but will allow:
- two different versions of PostgreSQL
- separate user lists

Does that help?
--
Richard Huxton
Archonet Ltd