During the normal course of transaction processing, the Inter-Request State-Management Service, the IdP Session Registry Service, and the SP Session Registry Service manage memory as part of normal processing. However, it is common for end users to abandon web sessions, resulting in orphaned data. To ensure that such data does not result in excessive memory usage, the data structures used by these services employ a least-recently-used (LRU) algorithm to purge old data. When a data structure reaches the maximum size, the oldest entries are automatically removed.
The maximum size of each data structure is configurable in the file size-limits.conf in the <pf_install>/pingfederate/server/default/conf directory.