PH53700: HIGH CPU IN MSTR WHEN USING INTEGRATED SYNCHRONIZATION IN DATA SHARING WITH LOW LOG VOLUME

APAR status

• Closed as program error.

Error description

• When Integrated Synchronization (Insync) is used in a data
  sharing group to synchronize data to IBM Db2 Analytics
  Accelerator or IBM Db2 for z/OS Data Gate it may cause an
  unusually high CPU consumption (TCB time) in MSTR address space
  for small to medium log record volumes.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Db2 12 for z/OS and Db2 13 for z/OS                      *
  * users who either use IBM Db2 Analytics                       *
  * Accelerator with IBM Integrated                              *
  * Synchronization or IBM Db2 for z/OS Data                     *
  * Gate in a data sharing environment.                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * High CPU consumption in MSTR address                         *
  * space in data sharing systems with a                         *
  * low to medium log write rate when                            *
  * synchronizing tables with Integrated                         *
  * Synchronization.                                             *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply corrective PTF when available                          *
  ****************************************************************
  In data sharing systems there is a noticeable CPU overhead
  involved when the current end of log is determined for all
  members. In data sharing systems with low to medium log write
  rates it is possible that the log reading task for Integrated
  Synchronization needs to determine the end of the current log
  very frequently in an attempt to collect any new log records
  as soon as they become available.
  This can cause an unusually high CPU consumption in the MSTR
  address space for data sharing systems with low to medium log
  write activity. High and very high log write activities are
  not affected by this overhead.
  Additional Keywords:
  IDAAV7R5/K DATAGATE/K
  

Problem conclusion

• Code has been changed to dynamically adjust the minimum time
  between calls to log manager that need to determine the current
  end of log while still providing log records with low latency.
  

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:

  UI91651 UI91652

Modules/Macros

• DSNILGRT DSNLJMCF DSNLJMLR
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI91651

     UP23/05/10 P F305

• RD10 PSY UI91652

     UP23/05/10 P F305