PH28141: OUT OF MEMORY IN CELL POOL USING 500 CONNECTIONS.

APAR status

• Closed as program error.

Error description

• Using a connection pool of 500 in Liberty:
  <connectionManager
  maxPoolSize="500" />
  
  causes connection failures with message
  CWWKX8057I and OOM in cell pool storage.
  

Local fix

• Reduce the number of connections.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server Liberty for z/OS                     *
  ****************************************************************
  * PROBLEM DESCRIPTION: z/OS Local Comm above the bar storage   *
  *                      issues in client address space          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The OLA getConnection API has a cell pool limit of 768
  conncurrent connections.  If the client address space exceeds
  that limit then they will receive an out of memory type of
  return.  The connection storage is obtained from a Local
  Communication (LCOM) cell pool within the BBGZLOCL structure.
  It currently supports a maximum of 768 allocated cells.
  
  Also, a couple small LCOM structure leaks were detected in the
  client address space.
  
  Under two scenarios there is a chance of leaking Local Comm
  queue elements.  The leak is in shared above the bar storage.
  This storage will be released when the bind is broken between
  the server and the client.  However, if the server and client
  are long lived then the leak may build over time.
  
  There are eye-catchers in the leaked queue elements: BBGZLDQE
  and BBGZLWQE.  The two scenarios involved in the leak occur
  during an attempt to queue a new element.
  
  First, if a queue limit has been reached which indicates that a
  side of the connection is being severely overrun.
  
  Second, the state of the associated connection is currently
  closing or cleaning up during the queuing attempt.
  
  In both of the above scenarios a newly created queue element
  failed to queue and is not freed.
  

Problem conclusion

• Code has been modified in Local Comm storage management for
  Connections in the client to allow more conncurrent connections.
  Also, code has been modified in the Local Comm native queue
  routines to free a queue element if it failed to be added to the
  target queue.
  
  The fix for this APAR is currently targeted for inclusion in fix
  pack 20.0.0.10.  Please refer to the Recommended Updates page
  for delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

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:

Fix information

• Fixed component name

  LIBERTY PROF -

• Fixed component ID

  5655W6514

Applicable component levels