Re: Exporting TBs of data in Oracle schema/database into CSV format to migrate into PostgreSQL

Hi,
On Mon, Apr 20, 2020 at 12:31 PM Scott Ribe <scott_ribe(at)elevated-dev(dot)com>
wrote:

> So, the big question is: how much downtime can you afford on the current
> Oracle DB?
>
> Yes, you should investigate the most efficient way to transfer data, but
> with TBs it will still be significant time. If you can afford the down
> time, great--kill all other connections to Oracle and go for it. If not,
> that's more complicated since you'll have to figure out a way to track and
> apply changes that happen during the copy...
>
If downtime is a concern, then, start a transaction on PG, using isolation
level - REPEATABLE READ, get the SCN number from Oracle and copy the
existing data from each table (table by table) using FDW for the initial
data load. And then, if you have Oracle GG license, start the replicat from
that SCN so that the data gets to sync eventually.
And then, when all the tables are in Sync, go ahead and switch your Apps.
If we dont have GG license, we need to look for some other extensions or
Kafka or something else that could do this job. Remember, migration is
always challenging when lots of data is involved, and there never exists a
direct magic.

--
Regards,
Avinash Vallarapu
+1-902-221-5976