PQ73853: Stateful session beans become zombies when client ends

 A fix may be available

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APAR status
Closed as program error.

Error description
There are many "zombie" stateful session beans in the J2EE
server region. They appear to be caused by terminating
communication with the clients. The deployment descriptor does
have the session timeout property specified, but it does not
seem to have any effect.
Local fix
ensure the ejbs are defined with an activation policy of
at-transaction, that the timeout value is reasonable (the
default is 8 hours) and that the BEAN_DELETE_SLEEP_TIME
environment variable for the server is set appropriately.
Passivated beans will be cleaned from the table according to the
interval (in minutes) specified by BEAN_DELETE_SLEEP_TIME.
Problem summary
****************************************************************
* USERS AFFECTED: All users of WebSphere Application Server    *
*                 V4.0.1 for z/OS and OS/390                   *
****************************************************************
* PROBLEM DESCRIPTION: Customers servers experience JAVA       *
*                      "Out Of Memory" errors after server has *
*                      been active for a short period of time. *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
JAVA "Out Of Memory" errors experienced when using activate once
Stateful Session Beans. Activate Once Stateful Session Beans
timeout value is not check unless the bean is referenced. If the
client of these beans goes away the reference is lost and the
bean will not be timed-out.
Problem conclusion
Code was added to periodically check for timedout Stateful
Session Beans. If the bean timeout value has ben reached the
bean is removed from the EJB container. The amount of time
between the check is controlled by the environment variable
BEAN_DELETE_SLEEP_TIME in current.env. The default is 70
minutes. The value is expressed in seconds eg: 60 minutes
equals 3600 seconds.

APAR PQ73853 requires a change a change to V4.0.1 WebSphere for
z/OS: Installation and Customization, GA22-7834-04 will be
available in the next refresh of the documentation. To access
the latest online documentation, go to the product library page
at:

www.ibm.com/software/webservers/appserv/zos_os390/

The change is to the table on page 397, which now reads:

|--------------------------------------------------------------|
| Env variable=<default>   | Dmn | SM  | Nam | IR  | App | zOS |
|--------------------------------------------------------------|
| ...                      |     |     |     |     |     |     |
|--------------------------------------------------------------|
| BEAN_DELETE_SLEEP_TIME=  |     | R^5 |     |     | O^20|     |
|  4200                    |     |     |     |     |     |     |
|--------------------------------------------------------------|
| ...                      |     |     |     |     |     |     |
|--------------------------------------------------------------|

and text on page 402, which now reads:

...
20. If you have an application that uses large numbers of
"activate once" stateful session beans, taking the default for
BEAN_DELETE_SLEEP_TIME could cause Java out of memory errors.

and text on page 413, which now reads:

BEAN_DELETE_SLEEP_TIME=n
The time in seconds allowed before an expired stateful session
bean's state is deleted from its backing datastore (DB2). The
default time is 4200 seconds (70 minutes). You can increase the
time to 2147483 seconds (24.85 days). Recommendation: Do not set
this variable less than 300 seconds (5 minutes).
Note: If you change the value of this variable for your
application server, you may also need to adjust the bean timeout
value for your stateful beans. The default stateful bean timeout
is 8 hours, which, when coupled with the BEAN_DELETE_SLEEP_TIME
default value, means it could take up to 9 hours and 10 minutes
to delete a bean. See WebSphere Application Server V4.0.1 for
z/OS and OS/390: Assembling J2EE Applications, SA22-7836, for
more information about stateful session bean timeout.
Example:
BEAN_DELETE_SLEEP_TIME=1000000

APAR PQ73853 is associated with SERVICE LEVEL W401507 of
WebSphere Application Server V4.0.1 for z/OS and OS/390.
Temporary fix Comments
APAR information
APAR number PQ73853
Reported component name WASKBASE
Reported component ID 5655A9801
Reported release 401
Status CLOSED PER
PE NoPE
HIPER NoHIPER
Submitted date 2003-05-05
Closed date 2003-06-16
Last modified date 2003-07-03

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Modules/Macros
BBOUBINF          

Fix information
Fixed component name WASKBASE
Fixed component ID 5655A9801

Applicable component levels
R401 PSY UQ77728    UP03/06/20 P F306

  Fix is available
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Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server for z/OS
Operating system(s):
Software version: 401
Software edition:
Reference #: PQ73853
IBM Group: Software Group
Modified date: Jul 3, 2003