Data counters for this category contain usage information for HTTP sessions.
Counter definitions
| Name | Key | Description | Version |
| CreateCount | servletSessionsModule.createdSessions | The number of sessions that were created | 3.5.5 and later |
| InvalidateCount | servletSessionsModule.invalidatedSessions | The number of sessions that were invalidated | 3.5.5 and later |
| LifeTime | servletSessionsModule.sessionLifeTime | The average session life time in milliseconds (time invalidated - time created) | 3.5.5 and later |
| ActiveCount | servletSessionsModule.activeSessions | The number of concurrently active sessions. A session is active if the WebSphere Application Server is currently processing a request that uses that session. | 3.5.5 and later |
| LiveCount | servletSessionsModule.liveSessions | The number of sessions that are currently cached in memory | 5.0 and later |
| NoRoomForNewSessionCount | servletSessionsModule.noRoomForNewSession | Applies only to session in memory with AllowOverflow=false. The number of times that a request for a new session cannot be handled because it exceeds the maximum session count. | 5.0 |
| CacheDiscardCount | servletSessionsModule.cacheDiscards | The number of session objects that have been forced out of the cache. A least recently used (LRU) algorithm removes old entries to make room for new sessions and cache misses. Applicable only for persistent sessions. | 5.0 |
| ExternalReadTime | servletSessionsModule.externalReadTime | The time (milliseconds) taken in reading the session data from the persistent store. For multirow sessions, the metrics are for the attribute; for single row sessions, the metrics are for the entire session. Applicable only for persistent sessions. When using a JMS persistent store, you can choose to serialize the replicated data. If you choose not to serialize the data, the counter is not available. | 5.0 |
| ExternalReadSize | servletSessionsModule.externalReadSize | Size of the session data read from persistent store. Applicable only for (serialized) persistent sessions; similar to external Read Time. | 5.0 |
| ExternalWriteTime | servletSessionsModule.externalWriteTime | The time (milliseconds) taken to write the session data from the persistent store. Applicable only for (serialized) persistent sessions. Similar to external Read Time. | 5.0 |
| ExternalWriteSize | servletSessionsModule.externalWriteSize | The size of the session data written to persistent store. Applicable only for (serialized) persistent sessions. Similar to external Read Time. | 5.0 |
| AffinityBreakCount | servletSessionsModule.affinityBreaks | The number of requests that are received for sessions that were last accessed from another Web application. This value can indicate failover processing or a corrupt plug-in configuration. | 5.0 |
| SessionObjectSize | servletSessionsModule.
serializableSessObjSize | The size in bytes of (the serializable attributes of ) in-memory sessions. Only session objects that contain at least one serializable attribute object is counted. A session can contain some attributes that are serializable and some that are not. The size in bytes is at a session level. | 5.0 |
| TimeSinceLastActivated | servletSessionsModule.
timeSinceLastActivated | The time difference in milliseconds between previous and current access time stamps. Does not include session time out. | 5.0 |
| TimeoutInvalidationCount | servletSessionsModule.
invalidatedViaTimeout | The number of sessions that are invalidated by timeout. | 5.0 |
| ActivateNonExistSessionCount | servletSessionsModule.
activateNonExistSessions | The number of requests for a session that no longer exists, presumably because the session timed out. Use this counter to help determine if the timeout is too short. | 5.0 |
| Name | Granularity | Type | Level | Overhead |
| CreateCount | Per Web application | CountStatistic | All | Low |
| InvalidateCount | Per Web application | CountStatistic | All | Low |
| LifeTime | Per Web application | TimeStatistic | Extended | Medium |
| ActiveCount | Per Web application | RangeStatistic | All | High |
| LiveCount | Per Web application | RangeStatistic | Basic | High |
| NoRoomForNewSessionCount | Per Web application | CountStatistic | Extended | Low |
| CacheDiscardCount | Per Web application | CountStatistic | All | Low |
| ExternalReadTime | Per Web application | TimeStatistic | Extended | Medium |
| ExternalReadSize | Per Web application | TimeStatistic | Extended | Medium |
| ExternalWriteTime | Per Web application | TimeStatistic | Extended | Medium |
| ExternalWriteSize | Per Web application | TimeStatistic | Extended | Medium |
| AffinityBreakCount | Per Web application | CountStatistic | All | Low |
| SessionObjectSize | Per Web application | TimeStatistic | All | Max |
| TimeSinceLastActivated | Per Web application | TimeStatistic | All | Medium |
| TimeoutInvalidationCount | Per Web application | CountStatistic | All | Low |
| ActivateNonExistSessionCount | Per Web application | CountStatistic | All | Low |