HTTP Sessions List

Analysis of WebSphere Application Server® HTTP Sessions in the memory image.

One common class of problems is related to applications' usage of HTTP sessions. In addition to OutOfMemoryErrors, other issues include finding the contents of sessions, timeout values, session identifiers, and the applications to which the sessions belong. There are many implementation details that make finding sessions and their values non-trivial. These details include different class names across different versions of the product and multiple maps per session (one for persisted sessions and the other for non-persisted sessions, both of which might be active in a single session).

The HTTP Sessions List query will extract all of this information into a tree view. The columns below the dotted line in the figure are a continuation of the columns above.

WebSphere Application Server HTTP Sessions List query

Each session object can be expanded to reveal its key/value pairs. In Figure 9, there are five attributes in the session. Each key is of the form sessN and the value is a custom object. If the value is something other than a String, then the row can be expanded to reveal the object.

WebSphere Application Server HTTP Sessions List query with an expanded session and its attributes

This plug-in also works with PHD heapdumps, but most of the metadata will be missing and only the retained heap sizes of the attributes will be known.

The "Security User Name" column is only available when the Session Security Integration feature is enabled.

The retained heap column does not show a cumulative total because, in theory, more than one session can reference the same object, so we would double count. To get an accurate view of all of the memory retained by all sessions, use the Sessions Overview query.