PH38050: THE REFRESH PROCESS MAY BE ABLE TO FORGO THE POINT OF CONSISTENCY LOCK THAT IS OBTAINED BEFORE ROW DATA IS FETCHED

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• Before FETCHing row data to perform a Refresh of a source table,
  IIDR CDC for z/OS requests a shared lock on the source table in
  order to force any "flying" transactions with pending changes
  for the table to either COMMIT or ROLLBACK their changes.  Once
  the lock has been acquired, it is immediately released.  This
  establishes a Point of Consistency between the table and the DB2
  Log.  It may be that the subsequent cursor that FETCHES the
  table rows using an Isolation Level of CS (or higher) will
  effectively achieve the same integrity, rendering the shared
  lock unnecessary.
  

Local fix

• No local fix is available.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: User of IIDR CDC for z/OS who use the        *
  *                 "native" refresh for synchronizing the       *
  *                 source and target tables.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Prior to a refresh, a shared lock on    *
  *                      the table being refreshed is obtained   *
  *                      to establish a point of consistency     *
  *                      between the table and the DB2 Log.      *
  *                      This lock is unnecessary, since the     *
  *                      cursor being used will serialize the    *
  *                      table's contents as it sweeps forward.  *
  ****************************************************************
  The point of consistency lock being used prior to a refresh has
  been found to be unnecessary.
  

Problem conclusion

• The point of consistency lock has been bypassed.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UI77999

Modules/Macros

• CHCDTRD8 CHCDTRDB
  

Fix information

• Fixed component name

  INFO SRVR CDC Z

• Fixed component ID

  5655U7600

Applicable component levels

• RA21 PSY UI77999

     UP21/11/30 P F111

Fix is available

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