Start of changeCICS VSAM Transparency for z/OS, Version 1.2


General CICS file control considerations

When a VSAM file is added to the CICS® VT DST and the migration status is ACT, the VSAM base cluster associated with the file control entry is no longer accessed. There are a number of operational factors to be considered.

The CICS file control definition must exist post migration to DB2. The following file control attributes are no longer relevant after migration:

The following file control attributes continue to be relevant after migration:

Existing files defined as Opentime Startup should be changed to Opentime Firstref.

The CICS VT global user exit (GLUE) honours these status attributes if they are dynamically changed by, for example, the CEMT transaction or CICS Explorer®.

If you migrate files that are defined to CICS as user maintained data tables (UMDT) or CICS maintained data tables (CMDT), modify the file attributes to TABLE - No at the same time as you add it to the CICS DST. Potentially, the CICS VT GLUE may not be enabled sufficiently early in the CICS start-up process to handle data tables. To avoid potential performance bottlenecks associated with data tables, consider defining DB2 buffer pools exclusively for the appropriate tables.





Last updated: May 25, 2012 20:43:55
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