What Is The Basic Setup Of The Changed Data Capture (Journalization) Feature In ODI


What is the basic setup procedure for implementing the CDC (Journalization) feature in Oracle Data Integrator (ODI)?

Details of ODI CDC setup can be found in the documentation library under the “Change Data Capture” topic.

  1. In the Model move to the Journalizing tab and choose the Journalizing Mode.
    • Double-click Model – Journalizing tab – Journalizing Mode, click radio button there for Simple or Consistent Set.
    • Simple Journalizing tracks changes in individual Datastores in a Model by the use of triggers (Simple) and crated views and tables (consistent).
    • Consistent Set Journalizing tracks changes to a group of Model Datastores and takes into account the referential integrity between these Datastores. The group of Datastores journalized in this mode is called a Consistent Set.
  2. Then select the Journalizing Knowledge Module (KM).
    • Double-click Model – Journalizing tab – Journalizing KM – Choose from the drop down list.
    • This Knowledge module must be imported into the Project’s Journalization JKM branch to be available for selection.
  3. The Options window should appear below and presents the options associated with the JKM.
    • Click in the Value section of the Options window to get a drop down menu of values, which can be chosen or left as default.
  4. After Journalization is set up, drill down in the Models panel to the Datastores of the journalized Model.
  5. Add the Datastore(s) to CDC.
    • Right click on the Model, click on Changed Data Capture and then on the Add to CDC.
  6. For Consistent Set Journalization, the order of those Datastores must be set in the Model on the Journalized Tables tab.
  7. Add the subscriber(s) to CDC.
    • Right click on the Model – Changed Data Capture – Subscriber – Subscribe…
    • Add subscriber to the text box on upper right and click on arrow button to add to list click OK.
    • The Execution pop up window shows and click OK button to execute subscriber addition.
    • Check Operator for success in addition of subscriber.
    • Subscribers: CDC uses a publish/subscribe model. Subscribers are the consumers of the data or entities that use the changes tracked on a datastore or on a consistent set. They subscribe to a model’s CDC to have the changes tracked for them. Changes are captured only if there is at least one subscriber to the changes. When all subscribers have consumed the captured changes, these changes are discarded from the journals.
  8. Then from the Model start the Journal.
    • Right click on the Model – Changed Data Capture – Start Journal
    • The Execution pop up window shows and click OK button to execute the journal startup.
    • Check Operator for success of journal startup.
    • This operation creates views for CDC and either triggers and/or the tables for CDC in consistent set.
    • Following are examples of those names created by the Journal.
      • Tables
        • SNP_CDC_*
        • J$
      • Views
      • Triggers
        • DT$
  9. From the Datastore icons, look for the tiny green clock that represents a journalized Datastore, click the refresh button if necessary.
  10. If the clock persists as yellow:
    • Right click on the Model – Changed Data Capture – Stop Journal
    • Determine the issue with the journal and restart journal.
  11. To view changes made, right click on the journalized Datastore – Changed Data Capture – Journal Data.
  12. Restart Changed Data Capture (CDC) processing:
    • The Model / Datastore in question is already journalized, and the ODI journalizing infrastructure still exists in the respective Working schema.
    • One should not re-start the journalization of a Model and/or Datastore if a previous journalization is still active.
    • The re-journalization is not possible without having stopped the already active one.
    • Hence, first stop the existing journalization, then start the new journalization.

Journalizing Status

Datastores in Models or Mappings / Integration Interfaces have an icon marker indicating their journalizing status in Designer’s current context:

  • (green clock icon) OK:Journalizing is active for this Datastore in the current context, and the infrastructure is operational for this Datastore.
  • (yellow clock icon) No Infrastructure:Journalizing is marked as active in the model, but no appropriate journalizing infrastructure was detected in the current context.

    Journals should be started.

    This state may occur if the journalizing mode implemented in the infrastructure does not match the one declared for the Model.

  • (white clock icon) Remnants:Journalizing is marked as inactive in the model, but remnants of the journalizing infrastructure such as the journalizing table have been detected for this datastore in the context.

    This state may occur if the journals were not stopped and the table has been removed from CDC.

Thanks,

~KKT~

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