PH33864: NEW REORG OPTION TO MINIMIZE DURATION OF LAST LOG ITERATION

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• New REORG option to minimize duration of last log iteration
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Db2 12 for z/OS users of REORG                           *
  * SHRLEVEL CHANGE utility                                      *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * New function for REORG SHRLEVEL CHANGE                       *
  * utility to minimize duration of the                          *
  * last log iteration in the LOG phase                          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  This APAR introduces a new keyword option to the REORG SHRLEVEL
  CHANGE utility, LASTLOG YES|NO, to further minimize the
  application outage window in the last log iteration in the LOG
  phase.
  During the LOG phase of the REORG SHRLEVEL CHANGE utility, the
  utility would quiesce all of the read and write claimers, then
  perform one last round of log apply before advancing to the
  SWITCH phase.  Depending if there are any log records applied
  to the shadow data sets during this final log iteration, REORG
  might need to perform actions such as force write and final
  incremental copy to reflect the latest DML changes.  In order
  to minimize these processing costs during the outage duration,
  a new parameter LASTLOG YES|NO is added to the REORG utility,
  as described below.
  For REORG TABLESPACE utility syntax diagram:
  >--REORG TABLESPACE-->
  Change-spec:
        |--DELAY 1200-----|  |--LASTLOG YES--|
  >-----|-----------------|--|---------------|--->
        |--DELAY integer--|  |--LASTLOG NO---|
  For REORG INDEX utility syntax diagram:
  >--REORG--|--INDEX LIST listdefname--|--->
            |--index-name spec---------|
  Change-spec:
      |--DELAY 1200-----| |--LOGRANGES YES--| |--LASTLOG YES--|
  >---|-----------------|-|-----------------|-|---------------|->
      |--DELAY integer--| |--LOGRANGES NO---| |--LASTLOG NO---|
  LASTLOG
  Specifies whether the REORG SHRLEVEL CHANGE utility would apply
  any log records in the final log iteration in the LOG phase.
  By the specification of LASTLOG NO, it can help reduce the
  outage window by avoiding the costly sub processes (such as
  page sets force write) that occur in the final log iteration,
  but it might cause REORG to not be able to complete if there
  is no quiet window with the absence of concurrent DML
  activities.  LASTLOG specification is ignored for non-SHRLEVEL
  CHANGE processing, and LASTLOG NO requires the DRAIN ALL option
  to be in effect.
  YES
  REORG utility is to perform one final round of log apply after
  acquiring the drain all.  This ensures that the REORG would
  proceed to the SWITCH phase after completing the final round of
  log apply in the LOG phase. The default value is YES.
  NO
  REORG utility is to ensure that no log records are to be
  applied in the final log iteration.  When existing criteria is
  met for REORG to break in, REORG would first perform the drain
  all and then process the logs from the end of the last log
  iteration to current.  If any log records of the target objects
  are found in this final log iteration, REORG would dedrain the
  target objects and revert this final log iteration back to a
  normal log iteration.  When it is time to break in again in a
  future log iteration, REORG would repeat this cycle of drain
  all, log read, and dedrain logic until it can complete the
  final log iteration with no log records to apply. The reversion
  back to a normal log iteration due to the presence of logs
  counts as a drain failure for RETRY consideration, so a high
  RETRY value is recommended to lessen the impact of the
  repeating break in attempts.
  

Problem conclusion

Temporary fix

Comments

• Code has been modified to introduce the aforementioned
  new function to the REORG utility.
  

APAR Information

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

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

  UI80216 PH46524

Modules/Macros

• DSNUGDDM DSNURLOG DSNUGUCA DSNUGPRT
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI80216

     UP22/04/28 P F204

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.