gointoit的专栏

最最简单的原理图

ns.save( { userid: "a", ts: ISODate('2011-11-03 14:17:00'), length: 95 } ); db.sessions.save( { userid: "b", ts: ISODate('2011-11-03 14:23:00'), length: 110 } ); db.sessions.save( { userid: "c", ts: I