PM73179: THE CHECKPOINT ITASK OVERLAYS ECSA FOR TWO BYTES AT THE START OF A PAGE BOUNDARY. PRIOR PAGE IS A 12/09/18 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The IMS checkpoint ITASK overlays ECSA while creating
  an IMS TYPE47 checkpoint record. The overlay is always
  two bytes of zeros at the start of the next page of ECSA storage
  following the LGWA (Log Work Area, PSTLOGWA).
  This occurs because the CAPDBCNT field (Altered DB count) was
  not included in the total length of an MPR's active PST data
  while writing to the LGWA.                         .
  .
  This only happens when an MPP is the last TYPE47 entry that fits
  exactly at the end of the LGWA buffer.  The code in error was
  introduced via APAR PM52121.
  

Local fix

• Apply APAR fix when available
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: IMS V11 customers that have PM52121 and/or   *
  *                 PTF UK78835 installed.                       *
  ****************************************************************
  * PROBLEM DESCRIPTION: Two byte overlay of the area directly   *
  *                      behind the IMS CHECKPOINT ITASKS's      *
  *                      PSTLOGWA.                               *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  The code building the Type47 record in DFSRCP10 fails to account
  for a 2 byte field containing the number of changed databases.
  
  The problem occurs when a non-BMP region is being processed and
  will occupy the last entry in the record.  Since only BMP
  regions log databases, the count will be zero but the field that
  contains the count itself was not factored into the length
  calculation.  When the record was later built, the 2 byte
  database count field extended beyond the allocated storage in
  which it was being created.
  
  The overlay can cause unpredictable results depending upon
  what storage exists beyond the record.
  

Problem conclusion

• GEN:
  KEYWORDS:
  
  *** END IMS KEYWORDS ***
  DFSRCP10 will now include the length of the database count field
  when determining if a non-BMP region entry will fit into the
  allocated storage when building a Type47 record.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UK82181

Modules/Macros

• DFSRCP10
  

Fix information

• Fixed component name

  IMS V11

• Fixed component ID

  5635A0200

Applicable component levels

• R100 PSY UK82181

     UP12/09/29 P F209 «

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.