PH11200: HIGH CPU IN DIST ADDRESS SPACE AFTER APPLY PI99529

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• High CPU IN THE DIST ASID AFTER APPLY OF APAR  PI99529.
  
  Customer may see higher then usual cpu in the DIST address space
  with APAR PI99529 applied. An error in PI99529 results in
  a longer then expected chain of SPME blocks in an environment
  that contains similar IPADDResses for Db2 clients. CPU may
  increase over time for the DIST address space as the chain
  increases becuase the search time will then increase.
  
  Example of similar ipaddresses would be as follows (more
  likely to see the problem with CPU):
  100.1....
  100.2....
  100.3....
  
  
  This example list of ipaddresses would be considered unique:
  100.1...
  80.2...
  70.3...
  
  A system dump of Db2 will show numerous entries in systrace for
  EXT events which equate to DSNLQDIS+3776
  
  
  This problem may occur with or without System Profile Monitoring
  being enabled.
  

Local fix

• DDF stop and start are required to free the SPME blocks that
  have accumulated.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Distributed Data Facility (DDF) users    *
  *                 who have applied PI99529/UI58395,UI58393.    *
  *                 Specifically those with remote client        *
  *                 applications that access a Db2 for z/OS      *
  *                 server via TCP/IP.                           *
  ****************************************************************
  * PROBLEM DESCRIPTION: A System Profile SPME control block     *
  *                      chain erroneously accumulated excessive *
  *                      SPMEs over time after applying          *
  *                      PI99529/UI58395,UI58393. This may       *
  *                      result in higher CPU usage in the       *
  *                      xxxxDIST address space.                 *
  ****************************************************************
  * RECOMMENDATION: Apply corrective PTF when it is available.   *
  ****************************************************************
  Db2 System Profile Monitoring automatically collects information
  related to remote client applications that access Db2 via
  TCP/IP. An SPME control block is created for each unique IP
  address and stored in a hash chain.
  After applying PI99529/UI58395(V11),UI58393(V12), Db2 system
  profile logic incorrectly calculated the hash index for
  anchoring these SPME control blocks. As a result, over time,
  the hash chain (which is responsible for monitoring TCP/IP
  connections) accumulated an excessive number of SPME control
  blocks. This erroneously long chain led to longer processing
  time for Db2 when processing inbound TCP/IP connections because,
  for each connection, Db2 needs to determine if an existing
  SPME control block already exists or a new one is to be
  created. This error may ultimately cause higher CPU consumption
  within the xxxxDIST address space.
   Note: This problem can occur with or without System Profile
         started.
  

Problem conclusion

• Db2 System Profile Monitoring processing has been changed to
  correctly calculate the hash index for storing SPME control
  blocks related to inbound IP addresses from remote clients.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UI63291 UI63295

Modules/Macros

•    DSNLILNR
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RB10 PSY UI63295

     UP19/06/01 P F905 «

• RC10 PSY UI63291

     UP19/06/01 P F905 «

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.