PM07658: ABEND SYSTEM DC2 ABENDSDC2 DBFBPNS0 FPBP64=Y IARV64 RSN48004720 PAGE ALIGNMENT ERROR 10/02/15 PTF PECHANGE

Obtain the fix for this APAR

APAR status

• Closed as program error.

Error description

• Customer system had 179 DEDBs active with 2K CI size.
  Before PM01071, IMS calculated the size of the primary
  buffer pool extent as the larger of 16 or (# DEDBs/32 ).
  In this case, the result was 16 buffers. The secondary extent
  size in buffers is one half the primary size, so 8 buffers.
  Both are multiples of 4K so this was not a problem.
  PM01071 changed the calculation to divide by 8, not 32, which
  resulted in primary and secondary size in buffers of 22 and
  11, respectively ( since 22 > 16 ).
  11 2K buffers is a problem because it is not a multiple of 4k.
  The base code never checked this but it would have required
  far more DEDBs with 2K CI size ( minimum 544 ) to expose the
  problem.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: ALL IMSFP FPBP64 USERS. *
  ****************************************************************
  * PROBLEM DESCRIPTION: ABENDSDC2 due to only pagefixing a *
  * partial page. *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF *
  ****************************************************************
  When pagefixing a subpool extent, the extent size was '16'x
  (22d). The extent size was set at one half the base section
  size, which set the extent size at 'B'x (11d). As the buffer
  size was '800'x (2,048d), pagefixing 11 2k buffer resulted
  in pageifxing a partial page. This eventually caused a problem
  with Media Manager, resulting in the abend.
  ----------------------------------------------------------------
  note: The exposure only exists if the base section size for
  200x, 400x & 800x (512d, 1024d and 2048d) will *NOT*
  fill an entire IPAGE 1000x (4096d) when divided by 2
  and the subpool is extended.
  

Problem conclusion

• GEN:
  KEYWORDS:
  
  *** END IMS KEYWORDS ***
  When the extent size is calculated, the size will be rounded up
  so as to fill and entire IPAGE.
  
  DBFBPNS0:
  When the base section of the subpool is allocated, the extent
  size is calculated and stored into the BPND3 base block.
  The extent size will be rounded up to a full page for 200x,
  400x and 800x buffer sized subpools.
  

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:

  UK54703

Modules/Macros

DBFBPNS0

Fix information

• Fixed component name

  IMS V11

• Fixed component ID

  5635A0200

Applicable component levels

• R100 PSY UK54703

     UP10/03/04 P F003 ®

Fix is available

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