What is the purpose of the Retention Period in Client Activity Events?

The Retention Period is a grace window (measured in seconds) designed for network jitter mitigation. It prevents the 'ClientDisconnected' event from firing immediately if a client loses connection briefly. If the client reconnects within this window, the event is suppressed, reducing false alarms in unstable network environments.

Which NCache clients receive connect/disconnect notifications?

Any client application that has subscribed to the event callback (via the MessagingService API) will receive real-time updates when other clients join or leave the cluster.

Is there a performance overhead for enabling client activity monitoring?

The overhead is extremely low. These events are lightweight push-notifications that only fire upon a state change (connect/disconnect). NCache manages retention tracking efficiently, ensuring no impact on core data operations.

Client Activity Event Notifications

NCache provides Client Activity Events that allow clients connected to a clustered cache to subscribe to notifications about the connection and disconnection of other clients, enabling stateful monitoring of client connectivity within the cluster. A configurable Retention Period can be specified to define the grace interval after which a disconnected client is considered truly disconnected and its disconnection event is raised. If a client reconnects within this retention period, the disconnection event is suppressed to avoid false notifications caused by transient network issues. This mechanism accounts for accidental disconnections in unreliable network environments where the NCache client automatically reconnects without affecting client operations. Client Activity Events are disabled by default and must be enabled prior to use.

Note

This does not apply to clients that manually dispose and reinitialize themselves.

Using the NCache Management Center

Launch the NCache Management Center by browsing to http://localhost:8251 or <server-ip>:8251.
In the left navigation bar, click on Clustered Caches or Local Caches, based on the cache to configure.
Against the cache name, click on View Details.

Important

Ensure the cache is stopped before proceeding.

View Details Client Activity Events Web

This opens up the detailed configuration page for the cache. Go to the Advanced Settings tab and click on Options in the left bar.
Under Client Activity Notifications, select the Enable Client Activity Notifications checkbox.
Configure the Retention Period to define the time after which a disconnected client is considered disconnected.

Client Activity Events Web

Click on Save Changes present at the bottom of the page to apply this configuration to the cache.

Client Activity Event Notifications

Note

Using the NCache Management Center

Important

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