Postgres vs. Oracle

I have developed an inhouse database on PostgresSQL and management has now
decided they want to start using it for other purposes.  We need to decide
if we are going to stay with Postgres or move on to some other database.
Oracle is the one they are considering.  They are concerned that Postgres
won't handle large tables (50-100 megarows) and the higher volume accesses.

I myself am uncertain which would be better.  I am comfortable with
Postgres.  It has done most of what I needed.  I got a pre-release CD of
Oracle 8 for linux.  I never did get around to installing it but I did look
at the contents.  The main executable was 18MB.  I find it hard to belive
that any program that large would be quick. Any Thoughts?

How hard will it be to port Postgres 'C' code to Oracle?  All of my current
DB access is done via a thin 'C++' wrapper around the postgres 'C' library.
I have done ODBC code before and found it to be  much more complicated.
Does the Orcale API correspond more closely to PostGres, ODBC or is it it's
own animal.

Bryan White
ArcaMax Inc.
Yorktown VA
www.arcamax.com