Sunday Feb 08, 2015

Coming Up, the Los Angeles Coherence SIG on March 5th

This is a unique Oracle Coherence event in Los Angeles, where engineers, architects and product managers will provide a detailed overview of its innovative features and a preview of what's coming up in the next release.

A full agenda for the event and details about how to register are available on-line here. Some of the topics covered include: 
  • Strategic Direction and Roadmap for Coherence 
  • Coherence Data Management - from disk to data-centre 
  • Coherence in the Oracle Cloud 
  • Coherence and Java 8, "made for each other"
[Read More]

Coming Up, the London Coherence SIG on March 19th

The next London Coherence SIG will be on March 19th 2015. This is a great opportunity to hear from engineers, architects and product managers about innovative features, integrations with complimentary technologies and a preview of what's coming up in the next release and the Oracle Cloud.

A full agenda for the event and details about how to register are available on-line here. Some of the topics that will be covered include: 
  • Scalable real-time event processing with Coherence and Oracle Event Processor 
  • Coherence and Java 8 - seamless and asynchronous 
  • Coherence in the Oracle Cloud 
  • Coherence and Big Data, where do they fit?
[Read More]

Thursday Dec 05, 2013

New: VisualVM Plugin for Coherence - released through the Coherence Incubator

We are excited to announce the availability of the Coherence VisualVM developer plug-in which is part of the new Coherence Incubator 12.1.0 release.

The community plug-in allows developers to view summarised Coherence related statistics and information when connected to a JMX enabled Coherence cluster.  Information is collected and summarised from the various Coherence MBeans and displayed in a tabular and graphical format. You also have the ability to select various services and caches to display more detailed node level information about each.

Once installed you will see an additional 'Coherence' tab, when you connect to your Coherence process which is running an MBean server. If you select of this tab, a 'Cluster Summary' tab will be displayed.

Cluster Overview


The number of sub-tabs displayed varies depending upon what features you are using, but can include:

  • Cluster Overview - High-level information about the Coherence cluster including cluster name, version, member count and 'Cluster StatusHA'. Summary graphs show total cluster memory available and used, packet publisher and receiver success rates and load averages for machines running Coherence.
  • Machines - A list of the physical machines that make up the Coherence cluster as well as information about the load averages and available memory on these machines.
  • Members - The full list of Coherence members/nodes, including individual publisher/receiver success rates, memory and send queue sizes.
  • Services - Information about the running services including partition counts and statusHA values. If you select a service, on the next data refresh you will see detailed thread information for each node of the service as well as graphs of that information.
  • Caches - Displays information about any caches, including their size and memory usage information. To get the correct information to be displayed for memory usage, you must be using the binary unit-calculator. If you select a cache, on the next data refresh you will see detailed information about each node hosting that service and cache.
  • Proxy Servers - If your cluster is running proxy servers, this tab displays information about the proxy servers and the number of connections across each proxy server and total connections. You also have the ability to include or exclude the NameService.
  • Coherence*Web - If your cluster is configured for Coherence*Web, this tab displays information about the number of applications deployed, the number of HTTP sessions being stored as well as other information regarding session reaping.

A sample of the Members sub-tab is shown below, with visual clues - that are included on the various screens - to draw attention to potential issues.


The Services sub-tab below shows how to select an individual service and monitor detailed metrics, like as thread utilisation.


Getting the Plug-in

The plug-in is available from GitHub which hosts the source for the latest version of the Coherence Incubator (12.1.0).  The Incubator uses the Common Development and Distribution License (CDDL) license and the documentation, which includes how to build and install the plug-in, can be found here.  

A pre-built NetBeans Module (NBM) is available via or you can build as part of the Incubator above.

The VisualVM tool is available with any download of JDK 1.7 or at The Coherence plug-in is designed to work with JDK 7 Update 40 and above. 

If your cluster is running on an earlier version of Java, you can still use the latest JVisualVM and connect remotely to your cluster to view statistics.

Note: This is a developer tool for viewing information about a single cluster at a time. Other monitoring tools such as Oracle's Enterprise Manager or other 3rd party tools are suited for enterprise level monitoring, management and alerting. 

Thursday Jan 31, 2013

Monsanto Increases Throughput by 100x with Oracle Coherence

In the video below Andrew Montgomery, Solutions Architect at Monsanto, how Monsanto uses Oracle WebLogic Server and Oracle Coherence to drive new products forward. Andrew give Coherence credit for increasing the throughput of one their application by 100x, being the cornerstone of horizontal scalability and a major piece of technology in new applications at Monsanto. Take a look: 

Thursday Jan 17, 2013

Focus On The Community: Best practice when using Coherence Cache Listeners

Coherence cache listeners are a useful and popular feature that enable applications to react in real-time to events. Though easy to use they can also be misunderstood or abused. Here Alexey Ragozin explains how cache listeners work and provides some useful advice about how to avoid some pitfalls.

Asynchronous Cache Listener

Essential reading for anyone thinking of using this feature.

Thursday Dec 20, 2012

Focus On the Community: Ben Stopford

This is the first post in our "Focus on the Community" section of this blog.

Ben Stopford, Architect Engineering Lead specialising in Distributed Data at RBS Global Banking Markets, has been an active member of the Oracle Coherence community for a few years now. He has posted a number of valuable entries on his blog pertaining to the advanced usage of Coherence and Coherence patterns as well as speaking at a number of conferences including QCon, JavaOne and Oracle OpenWorld.

Head on over and check it out.


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