Removing a Master Site from a Master Group

After suspending the replication activity of a master group (Suspending Replication Activity for a Master Group), you can remove master sites from the master group. To remove a master site from a master group:

1. In Enterprise Manager, connect to the Database Instance Home page as the replication administrator.

2. Click Data Movement.

3. Under the Advanced Replication section, click Manage.

   The Administration Overview page appears.

4. Under the Multimaster Replication section, click the number link next to Master Groups to open the Master Groups page.

5. Select the target master group that contains the master site that you want to remove and click Edit.

   The General subpage of the Edit Master Group page appears.

6. Click Master Sites.

   The Master Sites subpage of the Edit Master Group page appears.

7. Select the master sites that you want to remove from the master group and click Remove.

After you have removed the master sites, generate replication support for all master group tables (Generating Replication Support for All Master Group Tables), optionally apply the administrative requests (Applying Administrative Requests) that result from your changes at all master sites, and then resume replication activity for the master group (Resuming Replication Activity for a Master Group).

If you would like to use APIs to remove a site without quiescing, refer to Special Circumstances for more information.

Special Circumstances

The sites being removed from a master group do not need to be accessible. When a master site will not be available for an extended period of time due to a system or network failure, you might decide to drop the master site from the master group. However, because the site is unavailable, you most likely cannot suspend replication activity for the master group. You can use the REMOVE_MASTER_DATABASES procedure in the DBMS_REPCAT package to remove master sites from a master group, even if the master group is not quiesced.

If this is the case, you are responsible for:

• Cleaning up the deferred transaction queue

• Removing any data inconsistencies

Specifically, the next time that you suspend replication activity for a master group, you must complete the following steps as soon as possible after the unavailable master sites are removed:

1. Suspend replication activity for a master group. See Suspending Replication Activity for a Master Group for instructions.

2. Remove all deferred transactions from each master site where the destination for the transaction is a removed master site. See Removing Deferred Transactions for instructions.

3. Remove all deferred transactions from removed master sites, as soon as they become available.

4. Re-execute or delete all error transactions at each remaining master site. See Removing Deferred Transactions for instructions.

5. Ensure that no deferred or error transactions exist at each remaining master. If you cannot remove one or more deferred transactions from a remaining master, execute the DBMS_DEFER_SYS.DELETE_TRAN procedure at the master site using SQL*Plus.

6. Ensure that all replicated data is consistent. Use the DBMS_RECTIFIER_DIFF package to determine and fix differences.

7. Resuming replication activity for a master group. See Resuming Replication Activity for a Master Group for instructions.