What should be the value of thread-count in distributed cache?

The thread-count value specifies the number of daemon threads used by the distributed cache service. If zero, all relevant tasks are performed on the service thread. The Default value is 0 and can be override using the system property tangosol.coherence.distributed.threads. This value will increase the parallelism of the processing in the Coherence Grid provided the edition used in Enterprise or Grid and not Standard.

It is recommended to set the value to 0 for scenarios with purely in-memory data (no read-through, write-through, or write-behind) and simple access (no entry processors, aggregators, and so on). For heavy compute scenarios (such as aggregators), the number of threads should be the number of available cores for that compute. For example, if you run 4 nodes on a 16 core box, then there should be roughly 4 threads in the pool. For IO intensive scenarios (such as read through, write-through, and write-behind), the number of threads must be higher. In this case, increase the threads just to the point that the box is saturated.

Remember, each service instance has its own primary thread. This thread has the option of using its own isolated thread pool if the thread-count is greater than zero. If the thread-count is zero, then all work will be performed by the primary service thread. If the thread-count is greater than zero, then all work will be performed by the thread pool (the primary thread acts as a task coordinator). The thread-count is per-service and per-cluster-member. Each cache service has a unique name. The CacheFactory class uses a single cache service instance for each cache type (Replicated/Distributed/etc). If you manually create additional cache services, they will each have their own isolated thread pools.