PI52278: IMS DEDB FAST RECOVERY ENHANCEMENT IN SUPPORT OF IMS V13 APAR PM85341, PI35724 AND IMS V14 APAR PI42240.

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• IMS DEDB Fast Recovery enhancement to support the following IMS
  APARs:
  - IMS V13: PM85341 (PTF is UK95732) and PI35724 (PTF is UI28314)
  - IMS V14: PI42240 (PTF is UI28436)
  These IMS APARs allow IMS to tolerate a block sequence number
  that wraps back to zero.  Message DFS3253I has been removed
  and IMS will not issue ABEND 616 after the BSN reaches FFFFFFFF.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All IMS DEDB Fast Recovery Version 2         *
  *                 Release 2 (FMID=H1J2220) users in IMS V13 or *
  *                 IMS V14.                                     *
  ****************************************************************
  * PROBLEM DESCRIPTION: This APAR is DFR version for following  *
  *                      IMS APARs:                              *
  *                      - IMS V13: PM85341 (PTF is UK95732)     *
  *                                 PI35724 (PTF is UI28314)     *
  *                      - IMS V14: PI42240 (PTF is UI28436)     *
  *                      These APARs allow IMS to tolerate a     *
  *                      log block sequence number (BSN) that    *
  *                      wraps back to zero from X'FFFFFFFF'.    *
  ****************************************************************
  * RECOMMENDATION: Apply the maintenance for this APAR.         *
  ****************************************************************
  - PI52278 for IMS DEDB Fast Recovery
  Every block of IMS log data ends with:
   - A fullword block sequence number (BSN)
   - A doubleword clock value
   - A doubleword log sequence number
  DFR is enhanced to support the BSN that wraps back to zero
  from X'FFFFFFFF' for IMS V13 and IMS V14.
  .
  Additional enhancement for DFR:
  The specification is changed so that DFR may determine the all
  log data sets necessary for running DFR by user's reply to the
  WTOR message MSGDFR3110A only if DFR is running in IMS V13 or
  IMS V14 and DBRC=N,AUTO=N is specified.
  This change improves the possibility for recovering DEDBs by
  DFR when X'4301' log records are inaccurate.
  

Problem conclusion

Temporary fix

Comments

• The following modules and macros have been modified.
  (x = D or E)
  *
  DFRRLGTx - This macro was modified as follows.
             . IMS APAR added a bit (LDSWRITN) to a LDSFLAG2 flag
               in a LCDSECT macro. This bit is set after a buffer
               has been successfully written to the OLDS.
               A bit (LDSWRITN) was taken in a RDSET DSECT as a
               new RLDFLAG2 (RLDWRITN) flag.
               This flag is used for a judgement of whether an
               entry of an OLDS entry table (DSET) is valid.
             . A new flag LOGSTAT3 (LOGBSN00) was added to a
               LOGTBL DSECT.
               This flag is used for a judgment of whether the
               block sequence number (BSN) has been set to a
               LOGTBSNF field.
             . A new flag RLGLRRST was added to a section of a
               'LOG READ RELATED.'
               Whenever a value is set to a RLGFBSEQ/RLGLBSEQ
               field, a RLGFBSUP/RLGLBSUP bit of the RLGLRRST flag
               is set.
  DFRCMDLx - This module was changed as follows.
             . The logic of the block sequence number (BSN)
               comparison was changed in the same manner as IMS
               APAR.
             . The following conditions were added for a judgement
               of whether to process an entry of the DSET.
                . A RLDPRIME bit or a RLDSEC bit in a RLDFLAG1
                  flag is set and the RLDWRITN bit in the RLDFLAG2
                  flag is set.
  DFRFDLWD - This module was changed so that the block sequence
             number (BSN) comparison might be made in the same
             manner as IMS APAR.
  DFRGAL2x - This module was changed as follows.
             . When DBRC=N,AUTO=N is specified, the WTOR message
               MSGDFR3110A is issued regardless of to the
               existence of the DSET.
             . The logic of the block sequence number (BSN)
               comparison was changed in the same manner as IMS
               APAR.
             . The following conditions were added for a judgement
               of whether to process an entry of the DSET.
                . A RLDPRIME bit or a RLDSEC bit in a RLDFLAG1
                  flag is set and the RLDWRITN bit in the RLDFLAG2
                  flag is set.
             . The value, which is used in order to judge whether
               the information on a restart checkpoint was gotten
               from the X'42' log records, was changed to a
               RSCDCHKP (CHECKPOINT-ID FOR RESTART) field from a
               RSCDCPBS (LOG BSEQ FOR RESTART CHKPT) field.
             . The value, which is used in order to judge whether
               a suffix of the OLDS block was saved, was changed
               to a RLGDATE (TOD) field from a RLGBSEQ
               (CURRENT BSN) field.
  DFRGCLSx - This module was changed as follows.
             . The logic of the block sequence number (BSN)
               comparison was changed in the same manner as IMS
               APAR.
             . The value, which is used in order to judge whether
               a previous OLDS was used, was changed to the DSN
               from the BSN which is acquired from DBRC.
             . When a null entry of the DSET is found, the
               searching a entry for the last OLDS is stopped.
             . When the entry of the DSET is for the last OLDS, a
               RLDBSEQF field and a RLDBSEQE field are updated
               with the actually read BSN unconditionally, and the
               RLDWRITN bit of the RLDFLAG2 flag is set.
             . When the RLGFBSEQ field is initialized, the
               RLGFBSUP bit of the RLGLRRST flag is turned off.
             . The RLGFBSUP bit of the RLGLRRST flag is used for
               the judgment of whether the value was set to the
               RLGFBSEQ field.
             . When a DFRGRD1x module with a GRDFNEXT request is
               called before an OLDSCLS subroutine is called, a
               RSCDCLOS bit (LAST OLDS ALREADY CLOSED) of a
               RSCDLSTF flag is temporarily set.
               This bit is used in order to prevent that the
               process of reading log records is stopped by the
               BSN which is set to a RSCDBSEQ field.
  DFRGDSCx - The condition, which is used in order to judge
             whether the OLDS was used, was changed as follows.
             . The RLDWRITN bit in the RLDFLAG2 field is set, or
               a RLDBLKNO field is not null and the RLDBSEQF field
               and the RLDBSEQE field are not equal.
  DFRGEFCx - This module was changed as follows.
             . The logic of the block sequence number (BSN)
               comparison was changed in the same manner as IMS
               APAR.
             . When a value is set to the RLGLBSEQ field, the
               RLGLBSUP bit of the RLGLRRST flag is set.
             . The RLGFBSUP bit of the RLGLRRST flag is used for
               the judgment of whether the value was set to the
               RLGFBSEQ field.
  DFRGRD1x - This module was changed as follows.
             . The logic of the block sequence number (BSN)
               comparison was changed in the same manner as IMS
               APAR.
             . When a value is set to the RLGFBSEQ field, the
               RLGFBSUP bit of the RLGLRRST flag is set.
             . The RLGFBSUP bit of the RLGLRRST flag is used for
               the judgment of whether the value was set to the
               RLGFBSEQ field.
             . When the last OLDS is already closed, i.e. when the
               RSCDCLOS bit of the RSCDLSTF flag is set, the
               RSCDBSEQ field still has X'FFFFFFFF' as an initial
               value set by DFRGCLSx.
               Thereby the process of reading log records is
               stopped after the BSN reaches X'FFFFFFFF'.
               This module was changed so that the RSCDCLOS bit of
               the RSCDLSTF flag might be used in order to prevent
               that the process of reading log records is stopped
               by the BSN which is set to a RSCDBSEQ field.
             . The value, which is used in order to judge whether
               the information on a checkpoint was gotten from the
               X'42' log records, was changed to the RSCDCCHK/
               RSCDCHKP field from the RSCDCCPB/RSCDCPBS field.
             . The following condition was added for a judgement
               of whether to set a INTPBUF bit of a TPBFRDF flag
               that indicates the log records are in temporary
               buffer.
                . The RSCDCLOS bit of the RSCDLSTF flag isn't set.
  DFRLCTLx - This module was changed as follows.
             . The condition, which is used in order to judge
               whether the block sequence number (BSN) has been
               set to a LOGTBSNF field, was changed as follows.
                . The LOGBSN00 bit of the LOGSTAT3 flag isn't set.
             . When the DBRC=N is specified and a X'4800' log
               record is read at the end, a value is not set to a
               RSCDLBSN field.
               However, since a DFRNLP2x module has to be changed
               to use the value of the RSCDLBSN field, the value
               of the RLGBSEQ field is copied to the RSCDLBSN
               field when a RSCDLP48 bit of a RSCDLPRC flag is
               set.
               And the RSCDLBSN field is initialized when the
               RSCDLP48 bit of the RSCDLPRC flag is turned off.
  DFRNLP2x - This module was changed as follows.
             . The logic of the block sequence number (BSN)
               comparison was changed in the same manner as IMS
               APAR.
             . In a SRCHBSN subroutine, a value of the RSCDLBSN is
               used as maximum of the BSN instead of X'FFFFFFFF'.
             . A new flag TARGBSNF (TARGBSNU) was added to the
               work area.
               This flag is used for a judgment of whether a
               value is set to a TARGBSN field.
             . When F'0' is found at least one in a value of a
               RCIEBSN field in a SRCHBSN subroutine, the process
               of reading log records for the the second log
               processing started from a checkpoint log record.
  DFRRSCDx - This module was modified to be re-assembled for
             reflecting the changes of a DFRRLGTx macro.
  *
  ========================
  = DOCUMENTATION CHANGE =
  ========================
  IMS DEDB Fast Recovery for z/OS Version 2 Release 2 User's Guide
  and Reference (Document Number: SC27-0928-04) should be changed
  as follows.
  ================================================================
    2.0 Program functions of IMS DEDB Fast Recovery
     2.3 OLDS processing
  .
  * The description has been changed as follows:
  .
       ...
       While reading the OLDS at the time of IMS failure, IMS DEDB
       Fast Recovery performs the following tasks according to its
       its log records:
       1. Time stamp verification
          ...
       2. Checkpoint ID table creation
          ...
  
       3. OLDS entry table creation
          If DBRC=N, IMS DEDB Fast Recovery creates an OLDS entry
          table (DSET) from the X'4301' log record
          (OLDS entry table log record).
  |       If IMS DEDB Fast Recovery is running in IMS Version 12
  |       or earlier, the table is used to determine the log data
          sets necessary for running IMS DEDB Fast Recovery.
  |       If IMS DEDB Fast Recovery is running in IMS Version 13
  |       or later and AUTO=Y is specified, the table is used to
  |       determine the log data sets necessary for running IMS
  |       IMS DEDB Fast Recovery.
  .
       If DBRC=N,AUTO=Y is specified,...
          ...
  .
       If DBRC=N,AUTO=N is specified, IMS DEDB Fast Recovery:
       - Searches for the X'42' log record until it is found.
  |    - Determines the log data set by the user's reply to the
  |      WTOR message that IMS DEDB Fast Recovery issues.
  .
       If DBRC=Y is specified,...
          ...
  ----------------------------------------------------------------
     2.5 Checkpoint determination
  .
  * The description has been changed as follows:
  .
       ...
       If DBRC=Y is specified in the EXEC parameter of IMS DEDB
       Fast Recovery, IMS DEDB Fast Recovery determines the log
       data set containing the recovery start checkpoint by using
       the OLDS/SLDS information in the RECON data set.
  |    If DBRC=N,AUTO=Y, the log data set is determined from the
       OLDS entry table (DSET) if it was created during the OLDS
  |    processing. If DBRC=N,AUTO=N, or if a DSET has not been
       created, or if SLDS contains the checkpoint, a WTOR
       message (DFR3110A) is issued. The operator must then reply
       with the DD name of the OLDS or SLDS that contains the
       checkpoint indicated by the DFR3301I message.
       ...
  ================================================================
    5.0 Recovering your IMS subsystem
     5.2 IMS recovery procedures
      5.2.3 Scenario 3: Recovering DEDBs without using RECON data
                        sets
       5.2.3.1 Recovering DEDBs without using RECON data sets
  .
  * The description has been changed as follows:
  .
       Before you begin
       ...
       About this task
       ...
       Procedure
       1. ...
          ...
       2. Determine the last and the previous OLDS.
          ...
          If the OLDS that was in use at the time of IMS failure
          or the previous OLDS contains a log record X'4301'
          (OLDS entry table log record), IMS DEDB Fast Recovery
          uses it to create an OLDS entry table (DSET) and
  |       determines the required OLDS. However, if DBRC=N,AUTO=N,
  |       or if a DSET is not created, or if an SLDS is required,
          you must specify the ddname and data set name of all
          OLDSs and SLDSs after IMS recovery start checkpoint
          (indicated by the message DFR3301I).
          ...
  *
  

APAR Information

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

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

  UI33351

Modules/Macros

• DFRCMDLD DFRCMDLE DFRFDLWD DFRGAL2D DFRGAL2E
  DFRGCLSD DFRGCLSE DFRGDSCD DFRGDSCE DFRGEFCD DFRGEFCE DFRGRD1D
  DFRGRD1E DFRLCTLD DFRLCTLE DFRNLP2D DFRNLP2E DFRRSCDD DFRRSCDE
  

Fix information

• Fixed component name

  DEDB FAST RECOV

• Fixed component ID

  5655E3200

Applicable component levels

• R220 PSY UI33351

     UP15/12/02 P F512

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.