AboutQuick Start
Products & Services
Training Dates
Apr 29-30, 2010
Jun 28-29, 2010
Oct 6-7, 2010
Nov 11-12, 2010
Dec 2-3, 2010
Feb 4-5, 2011
India - Delhi
Feb 4-5, 2010
June 17-18, 2010
Dec 2-3, 2010
See training details.
Blogs & Tweets
Remote Network debugging and monitoring for Distributed Caches
Introduction
The ehcache-1.x-remote-debugger.jar} can be used to debug replicated cache operations. When started with the same configuration as the cluster, it will join the cluster and then report cluster events for the cache of interest. By providing a window into the cluster it can help to identify the cause of cluster problems.
Packaging
From version 1.5 it is packaged in its own distribution tarball along with a maven module.
It is provided as an executable jar.
Limitations
This version of the debugger has been tested only with the default RMI based replication.
Usage
It is invoked as follows:
java -classpath [add your application jars here]
-jar ehcache-debugger-1.5.0.jar ehcache.xml sampleCache1
path_to_ehcache.xml [cacheToMonitor]
Note: Add to the classpath any libraries your project uses in addition to these above, otherwise RMI will attempt to load them remotely which requires specific security policy settings that surprise most people.
It takes one or two arguments:
- the first argument, which is mandatory, is the Ehcache configuration file e.g. app/config/ehcache.xml. This file should be configured to allow Ehcache to joing the cluster. Using one of the existing ehcache.xml files from the other nodes normally is sufficient.
- the second argument, which is optional, is the name of the cache e.g. distributedCache1
If only the first argument is passed, it will print our a list of caches with replication configured from the configuration file, which are then available for monitoring.
If the second argument is also provided, the debugger will monitor cache operations received for the given cache.
This is done by registering a CacheEventListener which prints out each operation.
Output
When monitoring a cache it prints a list of caches with replication configured, prints notifications as they happen, and periodically prints the cache name, size and total events received. See sample output below which is produced when the RemoteDebuggerTest is run.
Caches with replication configured which are available for monitoring are: sampleCache19 sampleCache20 sampleCache26 sampleCache42 sampleCache33 sampleCache51 sampleCache40 sampleCache32 sampleCache18 sampleCache25 sampleCache9 sampleCache15 sampleCache56 sampleCache31 sampleCache7 sampleCache12 sampleCache17 sampleCache45 sampleCache41 sampleCache30 sampleCache13 sampleCache46 sampleCache4 sampleCache36 sampleCache29 sampleCache50 sampleCache37 sampleCache49 sampleCache48 sampleCache38 sampleCache6 sampleCache2 sampleCache55 sampleCache16 sampleCache27 sampleCache11 sampleCache3 sampleCache54 sampleCache28 sampleCache10 sampleCache8 sampleCache47 sampleCache5 sampleCache53 sampleCache39 sampleCache23 sampleCache34 sampleCache22 sampleCache44 sampleCache52 sampleCache24 sampleCache35 sampleCache21 sampleCache43 sampleCache1 Monitoring cache: sampleCache1 Cache: sampleCache1 Notifications received: 0 Elements in cache: 0 Received put notification for element [ key = this is an id, value=this is a value, version=1, hitCount=0, CreationTime = 1210656023456, LastAccessTime = 0 ] Received update notification for element [ key = this is an id, value=this is a value, version=1210656025351, hitCount=0, CreationTime = 1210656024458, LastAccessTime = 0 ] Cache: sampleCache1 Notifications received: 2 Elements in cache: 1 Received remove notification for element this is an id Received removeAll notification.
Providing more Detailed Logging
If you see nothing happening, but cache operations should be going through, enable trace (LOG4J) or finest (JDK) level logging on codenet.sf.ehcache.distribution/code in the logging configuration being used by the debugger. A large volume of log messages will appear. The normal problem is that the CacheManager has not joined the cluster. Look for the list of cache peers.