PH28849: THE STORAGE USAGE IN DBM1 INCREASES CONTINUOUSLY. 20/09/01 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The storage usage in DBM1 increases continuously. The statistics
  trace indicates the increase is mainly in COMPRESSION
  DICTIONARY in "DBM1 STORAGE ABOVE 2 GB".
  
  For example:
  
  DBM1 STORAGE ABOVE 2 GB                                 QUANTITY
  --------------------------------------------  ------------------
  GETMAINED STORAGE                       (MB)           xxxxxx.x
    COMPRESSION DICTIONARY                (MB)           123456.7
  
  The storage leak happens when Db2 read and decompress the log
  records to fulfill the log request from IFI306 product.
  
  In serious cases, auxiliary storage shortage message appears:
  
  Eg.
  *IRA206I ssssDBM1 ASID 00nn FRAMES 0060529217 SLOTS 0014803464
  % OF AUX 69.2
  ssssDBM1 TERMINATED AT END OF MEMORY
  
  Additional keywords: DB2STGLK/K
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Db2 11 and 12 for z/OS users who                         *
  * use IFCID306 and have applied PH24165/                       *
  * UI69926(v11) or PH20625/UI68519(v12).                        *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * The storage usage of compression                             *
  * dictionary in DBM1 increases                                 *
  * continuously and either PH24165/                             *
  * UI69926(v11) or PH20625/UI68519(v12)                         *
  * was previously applied.                                      *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply corrective PTF when available                          *
  ****************************************************************
  After either PH24165/UI69926(v11) or PH20625/UI68519(v12)
  is applied, when the following conditions meet,the storage
  usage of the compression dictionary in DBM1 might increase
  continuously.
  1. Db2 application used IFCID306 to do the log read and
     decompression;
  2. The log record(s) contains one or more compressed record;
  3. It is not the first time Db2 try to find the dictionary,i.e.
     more than one log record(s) referring to the same dictionary
     and this dictionary has been found and is locating in the
     buffer pool.
  PH24165/UI69926(v11) or PH20625/UI68519(v12)fixed problems
  with infinite loop during commit, but exposed the base
  code issue. The internal data structure which remembers the
  last saved dictionary tablespace partition number, which is
  also the anchor for releasing dictionary storage areas was not
  set up correctly. This causes a storage leak.
  

Problem conclusion

• Db2 code has been modified to set up the internal data
  structure correctly to remember the last saved dictionary
  tablespace partition number, which is also the anchor for
  releasing dictionary storage areas.
  Keywords: DB2STGLK/K
  

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:

  UI71875 UI71876

Modules/Macros

• DSNIFDIC
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RC10 PSY UI71876

     UP20/10/10 P F010 ­

• RB10 PSY UI71875

     UP20/10/10 P F010 ­

Fix is available

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