PM27960: WLM Compressor Fix and Enhancements

Fixes are available

APAR status

Closed as program error.

Error description

This APAR contains a fix to optimize how the workload
management (WLM) component will compress and decompress data
being sent betweenprocesses. This is designed to reduce
compression overhead in large WebSphere Process Server or
service integration bus (SIBus) topologies, specifically with
a large number of destinations (more effective at 2,000 or more
destinations). It addresses scenarios in which many clusters
have been defined and one or more non-messaging engine (ME)
clusters are restarted while the messaging engine cluster is
running. A customer experiencing this may see the following:

ThreadMonitor W   WSVR0605W: Thread
"server.startup : 0" (00000038) has been active for 686179
milliseconds and may be hung.  There is/are 1 thread(s) in total
in the server that may be hung.
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:199)
at
com.ibm.ws.sib.jfapchannel.impl.ExchangeReceiveListener.waitToCo
mplete(ExchangeReceiveListener.java:235)

In addition this fixes a rare condition which could result in
compressed data being lost.  This would only occur if a series
of bytes to be compressed could not actually be compressed
(every byte was unique). This would then cause a potential loss
of data due to how WLM handled the uncompressed bytes.

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  IBM WebSphere Process Server users or users *
*                  of IBM WebSphere Application Server with    *
*                  service integration bus (SIBus)             *
*                  configurations.                             *
****************************************************************
* PROBLEM DESCRIPTION: Workload management (WLM) Compressor    *
*                      Fix and Enhancements                    *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
In scenarios in which many clusters have been defined
and one or more non-ME clusters are restarted while the
messaging engine cluster is running, a customer experiencing
this may see the following:

ThreadMonitor W   WSVR0605W: Thread
"server.startup : 0" (00000038) has been active for 686179
milliseconds and may be hung.  There is/are 1 thread(s) in total
in the server that may be hung.
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:199)
at
com.ibm.ws.sib.jfapchannel.impl.ExchangeReceiveListener.waitToCo
mplete(ExchangeReceiveListener.java:235)

Problem conclusion

This APAR contains a fix to optimize how the WLM component
will compress and decompress data being sent between
processes. This is designed to reduce compression overhead in
large WPS/SIB topologies, specifically with a large number of
destinations (more effective at 2,000 or more destinations).

In addition this fixes a rare condition which could result in
compressed data being lost.  This would only occur if a series
of bytes to be compressed could not actually be compressed
(every byte was unique). This would then cause a potential loss
of data due to how WLM handled the uncompressed bytes.

Although it is not recommended, the compression optimizations
can be removed and the code reverted back to the prior code if
problems are seen by setting a cell level custom property:

In the administrative console, go to the Custom properties
page for the cell.

System administration > Cell >  cell_name, and then, under
Additional Properties, click Custom Properties

Create a new custom property with a name of:

IBM_CLUSTER_USE_LEGACY_COMPRESSOR

and a value of true.  Save, Synchronize the nodes and restart
all of the processes in the cell to pick up this change.

The fix for this APAR is currently targeted for inclusion in
fix packs 6.1.0.37 and 7.0.0.17.  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 number
PM27960
Reported component name
WEBS APP SERV N
Reported component ID
5724H8800
Reported release
61I
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-12-01
Closed date
2011-03-02
Last modified date
2011-03-02

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
WEBS APP SERV N
Fixed component ID
5724H8800

Applicable component levels

R61A PSY
UP
R61H PSY
UP
R61I PSY
UP
R61P PSY
UP
R61S PSY
UP
R61W PSY
UP
R61Z PSY
UP
R700 PSY
UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"6.1","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
27 October 2021

Tips

PM27960: WLM Compressor Fix and Enhancements

Fixes are available

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APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

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

Fixed component ID

Applicable component levels

R61A PSY

R61H PSY

R61I PSY

R61P PSY

R61S PSY

R61W PSY

R61Z PSY

R700 PSY

Document Information

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