Cluster Counter

To use a counter in your Infinispan cluster, first you have to add the maven dependency to your project. As you can see, it is simple as doing:

After adding the module, you can retrieve the CounterManager and start creating and using counters.

Each CounterManager is associated to a CacheManager. But, before showing how to use it, first we have some configuration to be done.

There are two attributes that you can configure: The num-owner - that represents the number of copies of the counter’s value in a cluster; and the reliability - that represents the behavior of the counters in case of partitions.

Below, is the configuration example with their default values. XML:

Programatically:

Then, you can retrieve the CounterManager from the CacheManager, as shown below, and start using the counters!

A counter is identified by its name. Also, it is initialized with an initial value (by default 0) and it can be persisted, if the value needs to survive a cluster restart.

There are 2 types of counters: strong and weak counters.

The strong counter provides higher consistency. Its value is known during the update and its updates are applied atomically. This allows to set boundaries and provides conditional operation (as compare-and-set).

The weak counter provides eventual consistency and its value is not known during updates. It provides faster writes when comparing with the strong counter.