ERROR DESCRIPTION:
Currently CacheMonitor application fetches all the cache entries in memory
(on the JVM heap) in one go when the client clicks on 'Cache Contents'
link, stores all cache entries on the session and displays 100 entries at
a time. Under some circumstances the attribute on the session can be quite
large, such as >10 MB, some tests with WCS (WebSphere Commerce Suite)
application showed that the object that was created by CacheMonitor
application can be >40 MB. This can cause several problems, such as
OutOfMemory conditions on the heap, temporary performance degradation when
the large object is allocated on the heap, failures when this Dynacache
attribute is replicated across several nodes or persisted to a database.
We will need to create a new version of CacheMonitor application which
will not create a large object on the heap & which will not store it
(cache entries) on the session.
LOCAL FIX:
Not available at this time, the workaround is not to use CacheMonitor
application at all so that it will not create a large object on the heap.
PROBLEM SUMMARY
USERS AFFECTED:
All WebSphere Application Server users using the Cache Monitor
application.
PROBLEM DESCRIPTION:
Cache Monitor application triggering OutOfMemory condition.
RECOMMENDATION:
None
When viewing cache contents via the CacheMonitor application, Cache
Monitor saves all the cache contents as a request attribute and displays
them 100 at a time. This triggers an OutOfMemory condition.
PROBLEM CONCLUSION:
This apar fixes the OutOfMemory condition triggered by the Cache Monitor
application.
The fix for this APAR is currently targeted for inclusion in cumulative
fix versions 5.02.16 and 5.1.1.10.