Re: Online Oracle to Postgresql data migration

On Jan 16, 2008 1:31 PM, Dawid Kuroczko <qnex42(at)gmail(dot)com> wrote:

> On Jan 11, 2008 7:14 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
> >
> > On Jan 11, 2008 12:02 PM, Josh Harrison <joshques(at)gmail(dot)com> wrote:
> > > Hi
> > > We have an Oracle production database with some terbytes of data. We
> wanted
> > > to migrate that to Postgresql (rigt now...a test database and not
> > > production) database.
> > > What are the good options to do that?
> > > Please advise me on where to look for more information on this topic
> >
> > You're going to need to use your brain for a fair portion of this,
> > because how you use oracle will be just different enough from everyone
> > else that no boxed solution.
> >
> > You have two steps to work on. The first is the DDL, to create
> > equivalent tables in pgsql as in oracle, the second is to migrate over
> > your data.
> >
> > I've generally done the ddl conversion by hand in an editor, and
> > migrated data over with some scripting language like perl or php.
>
> If you are migrating terabytes don't use perl. I did some experimental
> "for fun" migration some time ago and DBD::Oracle worked remarkably
> slow... What you need is to get a program which will export data
> from Oracle as CSV. As far as I know Oracle does not provide such
> a tool (though it will import CSV happily through sqlldr),
> but you can Google out a C-code which does just that. I don't remember
> where I left if... :-(
>
> From that, you just need to stream CSV into PostgreSQL's COPY
> command. It worked FAST. Really.
>
> And be wary of data types conversion.
>
> In this case how do you migrate the simultaneous
updates/deletes/inserts, Since this is a production system, there are
everyday changes in the databse ?