IC64834: MEMORY LEAK IN APPLICATION HEAP CAUSED BY UDFS OR STORED PROCEDURES WHEN CLIENT AND SERVER HAS DIFFERENT CODE PAGE.

DB2 Version 9.7 Fix Pack 2 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• This memory leak is caused by running UDFs when the following
  two conditions are true:
  
  1) your clientapplication and database server has different
     code pages
  2) the connection concentrator is enabled. DB2 Connection
     concentrator is activated when you set the number of maximum
     logical agents (max_connections) higher than the number of
     coordinating agents (max_coordagents).
  
  You may experience frequent out of application heap error
  messages due to this. The error message may look something
  like this:
  
  SQL0954C  Not enough storage is available in the application
  heap to process the statement.  SQLSTATE=57011
  
  
  Running the following db2pd command will show you a single
  application heap increasing as you repeat the execution of the
  UDF:
  
  
  db2pd -db <dbname> -memblocks appctl top
  
  -------------------------------------------------
  Top memory consumers in AppCtl memory set:
  PoolID     PoolName   TotalSize(Bytes)     %Bytes  TotalCount
  %Count    LOC          File
       1         apph         4923381504      86.45     2562612
  1.68    117     3551095165
       1         apph          486051840       8.53     2531520
  0.17    117     3551095165
  
  -------------------------------------------------
  

Local fix

• Disabling connection concentrator will prevent the memory leak.
  
  NOTE: DB2 connection concentrator is activated when you set the
  number of maximum logical agents (max_connections) higher than
  the number of coordinating agents (max_coordagents).
  

Problem summary

• USERS AFFECTED:
  ===============
  Customer using version 9.5 and above on all platforms.
  
  PROBLEM DESCRIPTION:
  ====================
  It user application runs UDFs very frequently under the
  following two conditions, database will experience the memory
  leak in application heap and cause frequent out of memory
  errors:
  .
  1) your clientapplication and database server has different
     code pages
  2) the connection concentrator is enabled. DB2 Connection
     concentrator is activated when you set the number of maximum
     logical agents (max_connections) higher than the number of
     coordinating agents (max_coordagents).
  
  RECOMMENDATION:
  ===============
  Disabling connection concentrator will prevent the memory leak.
  

Problem conclusion

• Problem is first fixed in version 9.7 Fixpack 2.
  

Temporary fix

• Disabling connection concentrator will prevent the memory leak.
  

Comments

APAR Information

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

  LI75022

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

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• R970 PSY

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