auto closing session?

Hello, On my website i massively use session. And often times the webserver is lacking resources to process more queries, and thats where all my applications are failing. I issue a destroy session at the end of my transaction, but some users dont end their transaction and thats the big problem for me. How can i solve that problem? Is their a command that will auto destroy the session after 5hours or so? -- - Louie Miranda http://www.axishift.com