IBM Extended Cache Monitor for IBM WebSphere Application Server technology preview

The IBM Extended Cache Monitor for IBM WebSphere Application Server provides you with functionality not available with the cache monitor that is supplied with WebSphere Application Server.

September 2012 (First published 09 May 2007)

The IBM Extended Cache Monitor for IBM WebSphere Application Server provides you with functionality not available with the cache monitor that is supplied with WebSphere Application Server.

Introduction

The IBM Extended Cache Monitor for IBM WebSphere Application Server provides you with two functions that are not available with the cache monitor that is supplied with WebSphere Application Server. These two functions enable you to:

  • display the contents of object cache instances
  • display the Dynamic Cache mbean statistics for cache instances

If you are familiar with the Cache Monitor, you know that it provides the ability to display the contents of the servlet cache instances, but there is no way to look at the contents of the object cache instances. The object cache instances have been added to the selection list that use to only display the servlet cache instances. Therefore, all of the functions that exist for the servlet cache instances are now available for object cache instances as well. For example you can:

  • Display the contents of the cache instances.
  • Display the dependency ids of the cache instances.
  • Display the disk offload statistics and contents.
  • Invalidate cacheids.

There is one exception, for security reasons, we removed the ability to look at the contents of a cached object that resides in an object cache. Because of this change, the ability to invalidate a cached object has been added to the panel that displays the cache instance contents.

Note: Adding property com.ibm.ws.cache.CacheConfig.showObjectContents =true to either custom properties for the cache instance or to the WebSphere Application Server JVM property will allow contents to also be displayed for object cache instances.

With the ability to display the dynamic cache mbean statistics for cache instances, you can produce a table that displays the mbean statistics for any application server that contains the selected cache instance. The initial table shows just the statistics for the one application server where the cache monitor is being accessed. However, you can modify which application servers you wish to see statistics for via a selection list that allows you to add/remove application servers from the table. We also provide a screen that allows you to select just the statistics that you are interested in seeing.

By combining these two features, you can tailor the mbean statistics table to show only the statistics you want to see for only the application servers that you want to see them for.

Figure 1. WebSphere Enhanced Cache Monitor
WebSphere Enhanced Cache Monitor

Enhancements to the cache monitor for WebSphere Application Server V7

In additional to the above new features, the following enhancements have been made for the cache monitor for WebSphere Application Server V7:

  • the ability to look at the push-pull table associated with a cache instance
  • the ability to search memory contents, disk contents, and the push-pull table for cacheids using a regular expression
  • the ability to compare cache instances

Prerequisites

Must have at a minimum either WebSphere Application Server 6.0.2.17, 6.1, 7.0, 8.0, or 8.5.

Installation

Once you've downloaded WebSphere Enhanced Cache Monitor, you can install it as follows:

  1. Install the cache monitor as supplied by WebSphere Application Server. It will be in the installableApps directory for either your deployment manager or stand alone application server.
  2. Download the appropriate package for your WebSphere installation. Note that you need WebSphere 6.1 or higher or 6.0.2 or higher.
  3. Unzip the selected package.
  4. Using the administration console, stop the Dynamic Cache monitor application and then select it for update.
  5. For a 6.0 installation, select Partial application and browse to the cachemonitor602_update.zip file that was contained in your downloaded package.
  6. For a 6.1 installation select Replace, add, or delete multiple files and browse to the cachemonitor61_update.zip that was contained in your downloaded package.
  7. For a 7.0, 8.0, or 8.5 installation select Replace, add, or delete multiple files and browse to the cachemonitor7_update.zip that was contained in your downloaded package.
  8. Select Next and then OK to complete the installation.
  9. Restart the Dynamic Cache Monitor application.
  10. Access the cache monitor through http://"hostname":"application server port"/cachemonitor where hostname is the name of the system where you have a WebSphere Application Server installed and the port number is the default host port for that application server.

WebSphere Extreme Scale

By design, WebSphere eXtreme Scale is intended to be used for caches that are far larger than what can be stored within a single WebSphere Application Server JVM. With these large caches, it is possible for a wild-card-style search of cache entries, performed with the Extended Cache Monitor (which runs within a single JVM), to exceed the resources of the WAS JVM. This may cause OutOfMemory errors on the JVM, which can have potentially disastrous consequences on all the applications running within the same application server. Whenever OutOfMemory errors occur the JVM must be restarted to fully recover. Therefore, it is highly recommended that attempting to view either part or all of the cached contents through the existing Extended Cache Monitor's query function not be done on more than single specific cache entries. A special version of Extended Cache Monitor is now available that removes the ability to search/display the cache contents via wild card-style searches. However, this version of the Extended Cache Monitor does allow the user to specify a list of specific cache entries to display. It is strongly recommend that this version of the Extended Cache Monitor be used whenever WebSphere eXtreme Scale is used as the cache provider.

Note: this version of the Extended Cache Monitor will only work with WebSphere Application Server versions 7.0 and above.

When using this to monitor dynamic cache instances that are using either WebSphere Extreme Scale or WebSphere Extreme Scale Appliance as their implementation, dependency ID and template information for cached entries will not show unless the WebSphere Application Servers have this trace string set: com.ibm.ws.objectgrid.dynacache.entries.CacheEntryImpl=finest.

Forum and newsgroup

We would very much like to hear any comments you may have about this technology. Please feel free to post them on the WebSphere Application Server forum at: WebSphere Application Server forum.

Download

DescriptionNameSize
Downlooad IBM Extended Cache Monitor zipcachemonitor.zip314KB
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SITE_ID=1
Zone=WebSphere
ArticleID=210854
SummaryTitle=IBM Extended Cache Monitor for IBM WebSphere Application Server technology preview
publish-date=09092012