PH30397: INCREMENTAL UPDATES WITH INTEGRATED SYNCHRONIZATION MAY SHOW A LOW LATENCY VALUE IF READING FROM THE DB2 LOG IS SLOW

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The replication latency indicated for incremental updates using
  Integrated Synchronization to either IBM Db2 Analytics
  Acceleratoror IBM Db2 for z/OS Data Gate may show an incorrect
  low value when the actual reads from the Db2 for z/OS log are
  progressing very slow and are trailing far behind the current
  end of log, e.g. when reading from the archive log or when
  retrying to read a log record that temporarily failed
  decompression.
  
  Replication latency is reported in various locations:
  * Data Studio and DSM: in accelerator overview section as
    replication latency
  * -DISPLAY ACCEL(*) DETAIL: CURRENT REPLICATION
     LATENCY FOR THIS DB2 SYSTEM
  * IFCID 2, section Q8ST: field Q8STCRL
  Additional keywords: IDAAV7R5/K DATAGATE/K
  

Local fix

• n/a
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Db2 12 for z/OS users who either use                     *
  * IBM Db2 Analytics Accelerator with IBM                       *
  * Integrated Synchronization or IBM Db2 for                    *
  * z/OS Data Gate.                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Replication latency reported by IBM                          *
  * Db2 Analytics Acceleratoror or IBM Db2                       *
  * for z/OS Data Gate is very low when                          *
  * Db2 for z/OS is slow to read from the                        *
  * log.                                                         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply corrective PTF when available                          *
  ****************************************************************
  The replication latency shown for incremental updates using
  Integrated Synchronization to either IBM Db2 Analytics
  Accelerator or IBM Db2 for z/OS Data Gate may give an
  incorrect low value when the actual reads from the Db2 for z/OS
  log are progressing very slow, e.g. when reading from the
  archive log or when retrying to read a log record that
  temporarily failed decompression. In that case, the accelerator
  or the Data Gate instance may read log records faster from the
  memory buffer used by Integrated Synchronization than Db2 for
  z/OS can fetch more log records. The empty buffer would be
  interpreted as being current with reading from the log.
  Replication latency is reported in various locations:
  * Data Studio and DSM: in the accelerator overview section as
    replication latency
  * -DISPLAY ACCEL(*) DETAIL: CURRENT REPLICATION LATENCY FOR
     THIS DB2 SYSTEM
  * IFCID 2, section Q8ST: field Q8STCRL
  Additional keywords: IDAAV7R5/K DATAGATE/K
  

Problem conclusion

• Code in Db2 has been changed to indicate the current read
  position in the Db2 for z/OS log when buffers are currently
  empty.
  The PTF for this APAR requires a maintenance level of IBM Db2
  Analytics Accelerator which is higher than V7.5.3, or a
  maintenance level of IBM Db2 for z/OS Data Gate which is
  higher than V1.1 to show correct values for replication
  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:

  UI72591

Modules/Macros

• DSNILGRT DSNLJEMG DSNLJMCF DSNILGWD DSNLJMLR DSNTDSTE
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI72591

     UP20/11/24 P F011

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.