If you need to change the record layout of a VSAM source data set, 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 VSAM 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 VSAM 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.
1Stop data change activity on the VSAM source file on the z/OS system.
2Close the VSAM file in the CICS region.
3If you use PowerExchange Condense, verify that PowerExchange Condense has extracted all data from the PowerExchange Logger for z/OS log files.
4Verify that the PowerExchange (CICS/VSAM ECCR), the capture routine, has captured all change records up to the point at which change activity was stopped.
5Verify that the change records that were captured under the current definition have been extracted by VSAM CDC Connector and written to the target. Then stop all mapping tasks that extract change data for the source file.
6Shut down the PowerExchange Logger for Linux, UNIX, and Windows.
7In the PowerExchange Navigator, open the original VSAM capture registration and set its status to History.
8Change the VSAM file structure.
9Delete the extraction map.
10In the PowerExchange Navigator, create a new capture registration for the altered VSAM data set that reflects the changes. Include the following settings:
- In the Condense list, select Part.
- In the Status list, select Active.
11Open the VSAM file in the CICS region.
12Warm start the PowerExchange Logger for Linux, UNIX, and Windows.
13Alter the target table to reflect the source file changes, if necessary.
14In Data Integration, for each mapping that includes the source data set, perform the following steps:
- Select the Source transformation. Under Source Properties, either click the Synchronize button on the Fields tab or select the data set again in the Object field on the Source tab. Either action causes the PWX CDC Metadata Adapter to retrieve the updated extraction-map metadata.
- If you changed the target table, select the Target transformation. Under Target Properties, click the Synchronize button on the Target Fields tab or select the table again in the Object field on the Target tab.
- Edit the field mapping to reflect the added or removed columns.
15If necessary, rematerialize the target tables.
16In 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.
17Allow updates to be made to the VSAM data set again.