Selecting a new journal table

The CDC Replication Engine for Oracle databases (Trigger edition) uses journal tables to detect and replicate database changes to the target table. You can change the journal table you had selected in the Map Tables wizard.

About this task

If you have mapped your source and target tables and have enabled Mirror (Change Data Capture) in the Map Tables wizard, then you have already selected a journal table. CDC Replication creates this table and uses it to track the database operations that occur on your source system. Each time there is a new row-level operation on your source table, a trigger executes in response to the database operation and CDC Replication reads the journal table to identify the database operation that occurred. CDC Replication then scrapes the database operation from the journal table and replicates it to the target.

If you want to change the journal table you had selected in the Map Tables wizard, then you must change the replication method to Refresh so that CDC Replication can disassociate the journal from the source table. You can then change the replication method back to Mirror and select a new journal table that you want CDC Replication to use.

Procedure

  1. Ensure that you have ended replication on the subscription.
  2. Click Configuration > Subscriptions.
  3. Select the subscription that contains the mapped source and target tables.
  4. Select a table mapping.
  5. Right-click and select Change Replication Method.
  6. Select Refresh.

    This disassociates the journal table from the source table. If you are using this same source table in other subscriptions, then you must set the replication method to Refresh for these subscriptions as well. CDC Replication disassociates the journal table from the source table in each subscription.

  7. Click OK.

    The table mapping should have a replication method and status of Refresh/Refresh.

  8. Select the same table mapping and click Change Replication Method.
  9. Select Mirror.

    This lets you select a new journal table.

  10. Select one of the following options and click OK.
    Use Default Journal
    Enable when you want the CDC Replication Engine for Oracle databases to use the default journal table provided with the CDC Replication Engine for Oracle databases: <TS SCHEMA>.DMCJRN. CDC Replication uses this journal table to detect and replicate database changes from the source to the target.
    Use Selected Journal
    Enable when you want the CDC Replication Engine for Oracle databases to use another journal table other than the default journal table provided with CDC Replication Engine for Oracle databases. When you select the database owner and provide a name for the journal table, the CDC Replication Engine for Oracle databases creates this new journal table and uses it to detect and replicate database changes from the source to the target.
    Owner
    Lists the database owner of the journal table.
    Name
    Lists the name of the journal table.