Offline sessions preloading

In addition to Infinispan caches, offline sessions are stored in a database which means they will be available even after server restart. By default, the offline sessions are not preloaded from the database into the Infinispan caches during the server startup, because this approach has a drawback if there are many offline sessions to be preloaded. It can significantly slow down the server startup time. Therefore, the offline sessions are lazily fetched from the database by default.

However, Keycloak can be configured to preload the offline sessions from the database into the Infinispan caches during the server startup. It can be achieved by setting preloadOfflineSessionsFromDatabase property in the userSessions SPI to true.

The following example shows how to configure offline sessions preloading.