PH43178: SDEP SEGMENTS "LOST" DUE TO DBFUMDL0 ( SDEP DELETE ) MOVING XVAL PAST CURRENT SDEP CI.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The following scenario can cause SDEP DELETE to move DMACXVAL
  ( Logical Begin ) past the current SDEP CI.
  HWM owning system begins with no current or PACIs.
  A marker is inserted, causing allocation of CI1 as current CI
  and CI2 and CI3 as PACIs.
  The marker has timestamp T1.
  A SCAN and DELETE are run to this marker at time T2.
  CI2 and CI3 end up with DEFAULT DLETRBA SEGMENT with timestamp
  T2.
  The this process is repeated, and a new marker inserted into
  CI1 with timestamp T3. This process causes preallocation to
  occur again, and CI4,CI5,C6 are preallocated. SCAN and DELETE
  are at time T4, and CI4,CI5,CI6 are hardened with DEFAULT
  DLETRBA SEGMENTs with timetampe T4. During or after DELETE,
  a BMP inserts SDEP segments that fill CI1,CI2,CI3,CI4,CI5,CI6,
  all in same commit interval, with all segments having timesstamp
  T5. Note that CI2 and CI3, PACIs, were not rewritten with
  new default segments - they still contain, at time of DELETE,'
  segments with timestamp T2.
  When Delete runs, to marker with Timestamp T3, it reads CI1
  which contains marker segments with timestamps T1 and T3, and
  is not flagged as full. This is detected and message DF2645I
  Utility Stop UsedCI<CI1 rba> is produced. Because EXCLUDE is
  not specified, the marker timestamp T3 is incremented by 3 clock
  ticks when used as stoptime, so CI1, does not actually contain
  any segment with TS GE the stoptime. It is not full, so is
  recorded, but processing continues and CI2,CI3,CI4,CI5,CI6 are
  read. CI2,CI3 contain default DELTRBA segments with timestamp
  T2, lower than T3, and DBFUMDL0 only checks for DEFAULT CURRENT
  segment, not DEFAULT DLETRBA segments, to stop. CI4,CI5,CI6
  are read and have timestamp T4, higher than the marker, so
  DELETE sets new DMACXVAL at CI4. The BMP ISRTs into CI1,CI2,CI3
  are below DMACXVAL and will not be returned on next SCAN.
  I think the DBFUMDL0, when looking at a NOT-FULL CI with
  only a DEFAULT segment within it, needs to check for 'DLETRBA'
  and 'SCANRBA' as well as 'CURRENT' when determining stop point,
  when thess segments have timestamps lower than the DELETE
  stoptime.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * IMS V15 Fast Path SDEP users                                 *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * SDEP SEGMENTS "LOST" DUE TO DBFUMDL0 ( SDEP DELETE ) MOVING  *
  * DMACXVAL PAST CURRENT SDEP CI.                               *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * INSTALL CORRECTIVE SERVICE FOR APAR/PTF                      *
  ****************************************************************
  SDEPs were ISRTed beyond highest prealloc CI after using SDEP
  DELETE utility (DBFUMDL0).  The next SDEP SCAN was not able to
  read these SDEPs.
  

Problem conclusion

• DBFUMDL0
  
  Code added to skip setting DMACXVAL for current or not full CI.
  

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:

  UI80488

Modules/Macros

• DBFUMDL0
  

Fix information

• Fixed component name

  IMS V15

• Fixed component ID

  5635A0600

Applicable component levels

• R500 PSY UI80488

     UP22/06/04 P F206

Fix is available

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