Liferay 6.2 Session autoextend Disadvantages

Question

I found that it's possible to automatically extend Liferay's session. So that the session doesn't expire till you close your browser. Is there any limitations or disadvantages of such approach. Any performance degrade or load issues?

Answer 1

As with any abstract question about hypothetical performance impact (or preliminary optimization) this question is basically unanswerable - but here's some criteria:

Naturally, pinging the server in order to extend a session will incur some extra load - if that results in a performance decrease, you'll most likely have a highly congested installation in the first place. If your server is bored all day, the extra ping won't bring it down.

You may or may not have custom applications running in your installation that store data in the user's session. If those are a few bytes (like Liferay does, e.g. the currently logged in user's information): There's probably no degradation. If you store 1MB of information per session (in your own custom apps - Liferay doesn't do this), things might differ: Just multiply your session storage size by the number of concurrent users that you expect. In case this use of memory indicates a problem: Make your custom apps use the session less - it's bad style anyway.

Will your particular installation suffer from any degradation? Measure. There's no way around this.

From a system maintenance point of view: If you're running a cluster and want to take individual machines out of the load balancer: Artificially extending sessions might indicate that a machine still has sessions open, even though they're mostly on unattended browsers - you'll get inflated numbers and it takes longer to bring machines down when you need to wait for the session count to come close to zero.