Enrico, Thanks for your reply.
Still I cannot understand how session expire detected on client side. The only codepath KeeperState.Expired generated is ClientCnxn#onConnected. It seems only called on client successfully connected to server. However, session could expire after connection established. Where is the latter case trigger? Best, tison. Enrico Olivelli <[email protected]> 于2019年9月24日周二 下午8:06写道： > Zili, > Sessions expire in the server. If you are not connected to the cluster you > cannot assume that the session is expired. > > There is another weird edge case: if the server/cluster is down the session > cannot expire. > > Hope that helps > Enrico > > Il mar 24 set 2019, 13:54 Zili Chen <[email protected]> ha scritto: > > > Hi ZooKeepers, > > > > I want to trace where Watcher.Event.KeeperState.Expired generated and it > > seems only generated > > when connect to server fails due to exceed session timeout. > > > > Besides, I find code snippet in ClientCnxn as below > > > > void queueEvent(String clientPath, int err, Set<Watcher> > > materializedWatchers, EventType eventType) { > > KeeperState sessionState = KeeperState.SyncConnected; > > if (KeeperException.Code.SESSIONEXPIRED.intValue() == err > > || KeeperException.Code.CONNECTIONLOSS.intValue() == err) { > > sessionState = Event.KeeperState.Disconnected; > > } > > WatchedEvent event = new WatchedEvent(eventType, sessionState, > > clientPath); > > eventThread.queueEvent(event, materializedWatchers); > > } > > > > which seems a bit wried to me what we queue > > a Event.KeeperState.Disconnected on > > KeeperException.Code.SESSIONEXPIRED. > > > > Back to the question, how zookeeper discovers and triggers session expire > > event on > > session expired after connection established successfully? > > > > Best, > > tison. > > >
