Heap Memory
Learn about memory based sessions, dead time memory wastage, undesirable low memory situations, and reclaiming reachable objects to avoid out-of-memory errors.
Memory-based session
One such hard limit is memory available, particularly in interpreted or man-aged code languages. Take a look at the following figure. Excess traffic can stress the memory system in several ways. First and foremost, every user has a session in the back-end of a web app. Assuming we use memory-based sessions (see Off-Heap Memory, Off-Host Memory), for an alternative to in-memory sessions, the session stays resident in memory for a certain length of time after the last request from that user. Every additional user means more memory.
Saving the memory
During that dead time, the session still occupies valuable memory. Every object we put into the session sits there in memory, tying up precious bytes that could be serving some other user.
When memory gets short, a large number of surprising things can happen. Probably the least offensive is throwing an out-of-memory exception at the user. If things are really bad, the logging system might not even be able to log the error. If no memory is available to create the log event, then nothing gets logged.