PM39514: Fix async replication where CPU utilization grows as the number of entries increase.

Download WebSphere eXtreme Scale V6.1.0 Fix Pack 5 compatibility fix

APAR status

• Closed as program error.

Error description

• A replication query is used to find entries in the cache that
  have changed since the last replication event.  That query was
  O(N) in complexity, it scanned all entries in the partition.
  This results in longer query times as the number of entries
  increases which also causes higher CPU utilization.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of asynchronous replication.      *
  ****************************************************************
  * PROBLEM DESCRIPTION: When using                              *
  *                      asynchronous replication,               *
  *                      proessor utilization                    *
  *                      grows as the                            *
  *                      number of entries increases.            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The asynchronous replication path includes both
  intra-domain asynchronous replication and multi-master primary
  to primary
  replication.  When these paths are used, processor  utilization
  grows as the number of entries increases and there are changes
  to be replicated.
  The problem is that the algorithm to calculate the changes to
  send searches for all entries within a window.  The current
  implementation needs to look at every entry to find all of the
  changes within the window.
  

Problem conclusion

• A new algorithm that searches for entries in constant
  time rather than linear time was implemented to improve
  performance.
  

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:

Fix information

• Fixed component name

  XD EXTREME SCAL

• Fixed component ID

  5724J3402

Applicable component levels

• R700 PSY

     UP