VSAM CDC Connector

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Handling changes to extraction maps

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.

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.

Stop data change activity on the VSAM source file on the z/OS system.

Close the VSAM file in the CICS region.

If you use PowerExchange Condense, verify that PowerExchange Condense has extracted all data from the PowerExchange Logger for z/OS log files.

Verify that the PowerExchange (CICS/VSAM ECCR), the capture routine, has captured all change records up to the point at which change activity was stopped.

Verify 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.

Shut down the PowerExchange Logger for Linux, UNIX, and Windows.

In the PowerExchange Navigator, open the original VSAM capture registration and set its status to

History

Change the VSAM file structure.

Delete the extraction map.

In 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

Open the VSAM file in the CICS region.

Warm start the PowerExchange Logger for Linux, UNIX, and Windows.

Alter the target table to reflect the source file changes, if necessary.

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.

If necessary, rematerialize the target tables.

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.

Allow updates to be made to the VSAM data set again.

Start the mapping tasks again.

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