[Java programming language only]

Configuring near-cache invalidation

[Version 8.6 and later]You can configure near-cache invalidation to remove stale data from the near cache as quickly as possible. When an update, deletion, or invalidation operation is run against the remote data grid, an asynchronous invalidation operation gets triggered in the near cache. This mechanism works more quickly than the other option of using time-to-live (TTL) eviction in the near cache.

Before you begin

  • You must be using IBM eXtremeIO. For more information, see Configuring IBM eXtremeIO (XIO).
  • You must be using a near cache. To determine whether near cache is enabled, run the BackingMap.isNearCacheEnabled() method in your client. For more information about configuring the near cache, see Configuring the near cache.

About this task

Enabling near-cache invalidation provides a more accurate set of data from the remote data grid because the near cache is updated when the remote data changes.

You can edit the necessary settings in the ObjectGrid XML file for your container server. The settings in this file apply to all clients, unless you override the settings. If you enable near-cache invalidation on the server, you can disable the near-cache invalidation on the client by overriding the nearCacheInvalidationEnabled attribute for the near cache with either XML or programmatic configuration. However, you cannot override the attribute to enable the near-cache invalidation when near-cache invalidation is disabled on the server. For more information about overriding client settings, see Configuring Java clients with an XML configuration and Configuring Java clients programmatically.

Procedure

  1. Set the nearCacheInvalidationEnabled attribute in the ObjectGrid descriptor XML file.
    Set this attribute on the backingMap element. For more information, see ObjectGrid descriptor XML file.
    [Version 8.6 and later]nearCacheInvalidationEnabled
    [Version 8.6 and later]Set the value to true to enable the removal of stale data from the near cache as quickly as possible. Any update , deletion, or invalidation operation against the data grid triggers an asynchronous invalidation in the near cache. Because the invalidation is asynchronous, client applications might access stale data for a short time period after an update has occurred before the stale value is removed from the near cache. To use near cache invalidation, the lockStrategy attribute must be set to NONE or OPTIMISTIC. To enable a near cache for a dynamic cache instance, this value must be set to true.

    Default: false (Optional)

  2. Restart the container servers and clients.
    For more information, see Starting and stopping stand-alone servers and Configuring container servers in WebSphere Application Server.