PK84528: IMPROVE THE PLUG-IN LOGIC FOR REQUESTING PARITION TABLES WHEN GETDWLMTABLE PROPERTY=TRUE AND A SESSION COOKIE IS DETECTED

Fixes are available

APAR status

Closed as program error.

Error description

When Memory To Memory Replication is enabled in a cluster
with the WebSphere plug-in property GetDWLMTable=TRUE, this
causes the other application servers in the cluster that have
Memory to Memory Replication disabled to continuously generate
the following message in the systemout.log.

[4/1/09 7:11:34:861 EDT] 000000f3 WebContainer  E   SRVE0017W: A
WebGroup/Virtual Host to handle /_WS/PT has not been defined.

In a large environment, this behavior generates an excessive
amount of logging for each appserver.

The preferred behavior is to only generate that message
for session requests when Memory to Memory Replication is
Enabled, the GetDWLMTable property=TRUE and a Session Cookie is
detected.

Local fix

Disable by updating the plug-in custom property to:
GetDWLMTable=FALSE

Problem summary

****************************************************************
* USERS AFFECTED:  All users of Web Server Plug-ins for IBM    *
*                  WebSphere Application Server who have       *
*                  Memory-to-Memory Session Replication        *
*                  configured on the Application Server.       *
****************************************************************
* PROBLEM DESCRIPTION: When custom property GetDWLMTable is    *
*                      set to TRUE all clusters in the         *
*                      WebSphere Cell are affected. But some   *
*                      clusters may not use memory-to-memory   *
*                      session replication. For these          *
*                      clusters, Plug-in unnecessarily sends   *
*                      a request for the Partition Table.      *
*                                                              *
*                      Secondly, for clusters that have        *
*                      Memory-to-Memory session replication    *
*                      configured and the Plug-in              *
*                      process handling an affinity request    *
*                      does not have a Partition Table,        *
*                      Plug-in only attempts to fetch          *
*                      the Table from one cluster member. If   *
*                      that cluster member is unreachable,     *
*                      then Plug-in uses Round Robin which     *
*                      may break affinity.                     *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
Plug-in's Session Handling function attempts to pre-fetch a
Partition Table when Memory-to-Memory Session Replication is
not configured.

Another deficiency reported is that when Memory-to-Memory
Session Replication is configured, a newly spawned Plug-in
process only attempts to fetch a Partition Table from only one
cluster member, if that request fails, Plug-in gives up and
uses either Round Robin or Random Load balancing to route the
user request. This may break affinity.
It is more desirable to have Plug-in attempt to fetch the
Partition Table from other cluster members if the first
attempt fails. This improves the chances of fetching a
Partition Table and hence reduces the occurrence of a break in
affinity.

Problem conclusion

Plug-in now has improvements in its Session Handling function
to ensure that when Memory-to-Memory Replication is not
configured for a cluster, no requests for a Partition Table are
sent for that cluster.

Also, when Memory-to-Memory Replication is configured, Plug-in
now attempts to fetch the Partition Table from other cluster
members if the first attempt fails.

The fix for this APAR is currently targeted for inclusion in
fix packs 6.0.2.39, 6.1.0.29 and 7.0.0.7. 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
PK84528
Reported component name
WEBS APP SERV N
Reported component ID
5724H8800
Reported release
60A
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2009-04-10
Closed date
2009-07-17
Last modified date
2009-12-10

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

R60A PSY
UP
R60H PSY
UP
R60I PSY
UP
R60P PSY
UP
R60S PSY
UP
R60W PSY
UP
R60Z PSY
UP
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":"6.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
28 December 2021

Tips

PK84528: IMPROVE THE PLUG-IN LOGIC FOR REQUESTING PARITION TABLES WHEN GETDWLMTABLE PROPERTY=TRUE AND A SESSION COOKIE IS DETECTED

Fixes are available

Subscribe

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

R60A PSY

R60H PSY

R60I PSY

R60P PSY

R60S PSY

R60W PSY

R60Z PSY

R61A PSY

R61H PSY

R61I PSY

R61P PSY

R61S PSY

R61W PSY

R61Z PSY

R700 PSY

Document Information

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