PM91835: LOOP IN SEARCHING FOR FREE SPACE POSSIBLE (ON CLASSIC-SEGMENTED TABLE SPACE)

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When searching for free space for classic-segmented table space,
  if the primary allocation is too small and the table has been
  altered, it is possible to be in a loop.
                                                         (167972)
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 10 and 11 for z/OS Users of          *
  *                 segmented or Universal table space           *
  ****************************************************************
  * PROBLEM DESCRIPTION: Looping during the insert transaction   *
  *                      when the system page is the last        *
  *                      segment of a space map page.            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When searching the available data page within a space map page,
  if it reaches the allowable locking failure threshold or
  page false lead threshold, the current space map page is
  skipped to enhance the space search performance.
  When determining the next space map page to search the last
  physical page is used to find the next anchor of the segment.
  However, if the last page of the current space map page
  is a system page then it is incorrectly used to determine
  the anchor linkage of the next segment.
  As the result, looping through visiting the same segment within
  the space map page may occurr.
  This enhancements only applies to the classic segmented table
  space with a single table or a Universal table space.
  

Problem conclusion

• DB2 code is modified to verify segment ID of the last segment
  within the current space map page.
  If the last segment does not belong to the current table,
  then the next search algorithm will be used.
  If the last segment belongs to the current table, then
  its segment anchor information is used to find the next
  segment for the table.
  

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:

  UK97588 UK97589 UK97590

Modules/Macros

• DSNISGSC
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UK97588

     UP13/10/01 P F309 ½

• RB10 PSY UK97589

     UP13/10/01 P F309 ½

• R910 PSY UK97590

     UP13/10/01 P F309 ½

Fix is available

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