Microsoft SQL Server CDC Connector > Microsoft SQL Server CDC administration > Handling changes to extraction maps
  

Handling changes to extraction maps

If you add or drop columns in a Microsoft SQL Server 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 MySQL 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 SQL Server 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. 1Stop data change activity on the SQL Server source table.
  2. 2Verify that any change data that was captured under the current table definition has completed SQL Server CDC Connector extraction processing. Then stop all mapping tasks that extract change data for the table.
  3. 3Shut down the PowerExchange Logger for Linux, UNIX, and Windows.
  4. 4In the PowerExchange Navigator, open the original capture registration and set its status to History.
  5. 5Add or drop columns in the source table.
  6. 6In the PowerExchange Navigator, create a new capture registration for the table that reflects the column changes. Include the following settings:
  7. 7Warm start the PowerExchange Logger.
  8. 8Alter the target table to reflect the source table changes, if necessary.
  9. 9In Data Integration, for each mapping that includes the source table, perform the following steps:
  10. 10If necessary, rematerialize the target tables.
  11. 11In 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.
  12. 12Resume change activity on the source table.
  13. 13Start the mapping task again.