4 Replies Latest reply: Jan 28, 2013 9:59 AM by 441858 RSS

    recovery catalog vs controlfile....database ID

    441858
      Oracle 11gR2 Linux RHEL6

      I was wondering why the recovery catalog will not allow you to store backups of databases that have the same DBID, but the controlfile will?

      I mean it makes complete sense why the recovery catalog gives you the 'RMAN-20004: target database name does not match name in recovery catalog' error in this instance, but why does the controlfile have no issue with that?

      Just wondering.

      Thanks.
        • 1. Re: recovery catalog vs controlfile....database ID
          mseberg
          Hello;

          A catalog storing backups with two databases with the same DBID would be a conflict. So a clone of a database with the same DBID would conflict with the catalog because without a unique DBID the catalog would have no way of knowing which database is which. If the catalog allowed duplicate DBID's restore/recover would be impossible as the catalog would not know which database it was working with.

          The control file of the clone with the same DBID will allow a backup because the control file is completely separate from the database it was cloned from.

          Best Regards

          mseberg
          • 2. Re: recovery catalog vs controlfile....database ID
            441858
            Thanks for your reply mseberg.
            The control file of the clone with the same DBID will allow a backup because the control file is completely separate from the database it was cloned from.
            I am not sure I follow. Doesn't the controlfile store the DBID as well? Doesn't the DBID get reset when we clone/duplicate a database from one db to another?

            Thanks.
            • 3. Re: recovery catalog vs controlfile....database ID
              mseberg
              OK;

              Think of the catalog database as global and the control file of the clone database as local. Since the control file is local to the clone database it can store any information it wants without conflict.

              The control file of the clone database is private to that database, so the DBID can be the same without conflict.

              The catalog database is not private so a duplicate DBID is a conflict. ( Public to the other databases in your system )

              Does that help?

              Best Regards

              mseberg
              • 4. Re: recovery catalog vs controlfile....database ID
                441858
                I see now. That makes sense.

                Thanks for the clarification!

                JrOraDBA