Db2 for z/OS CDC Connector > Db2 for z/OS CDC administration > Handling changes to extraction maps

Handling changes to extraction maps

If you add or drop columns in a Db2 for z/OS source table, you must create a new capture registration. PowerExchange generates an associated extraction map by default. Use the generated extraction map instead of creating a user-defined extraction map. The PWX CDC Reader on the Db2 for z/OS CDC Connector system will retrieve information from the new generated extraction map.
To switch to the new table definition and preserve access to previously captured data, you must perform several steps in both the PowerExchange and Db2 for z/OS CDC Connector environments.
Note: You do not need to perform these steps if you selectively capture change data for a subset of columns, and the DDL changes do not affect any of these columns.
  1. 1. Stop data change activity on the Db2 source table on the z/OS system.
  2. 2. Verify that the Db2 change capture routine (Db2 ECCR) has captured all change records up to the point at which change activity was stopped.
  3. 3. Verify that the change records that were captured under the current table definition have been extracted by Db2 for z/OS CDC Connector and written to the target. Then stop all mapping tasks that extract change data for the table.
  4. 4. Shut down the PowerExchange Logger for Linux, UNIX, and Windows.
  5. 5. In the PowerExchange Navigator, open the original capture registration and set its status to History.
  6. 6. Add or drop columns in the source table.
  7. 7. In the PowerExchange Navigator, create a new capture registration for the table that reflects the column changes. Include the following settings:
  8. 8. Issue the Db2 ECCR REFRESH command so that the PowerExchange change capture routine can use the new registration.
  9. 9. Warm start the PowerExchange Logger for Linux, UNIX, and Windows.
  10. 10. Alter the target table to reflect the source table changes, if necessary.
  11. 11. In Data Integration, for each mapping that includes the source table, perform the following steps:
  12. 12. If necessary, rematerialize the target tables.
  13. 13. In the mapping task, set a time-based restart point that coincides with the time of target rematerialization or let the mapping task restart from the last checkpoint that was recorded in the state table on the target.
  14. 14. Allow change activity to resume on the source table.
  15. 15. Start the mapping tasks again.