global variable accross sessions

How I can set up a global variable accross sessions, for instance, I want to count how many times a flow service be invoked.

I can set it up at database / file level, but I want to know if there is any other simple way, such as cache.

thanks,

Shuren

Keyword: Repository

Ray had written an excellent article long time back on this.

Though please note that this approach has its own Pro’s/Con’s.