Hi Ted, thanks for your reply.
> This page: about Zookeeper error > handling<http://wiki.apache.org/hadoop/ZooKeeper/ErrorHandling>may > help. I actually read this page before. You may have misunderstood my question. I know how to recover from the connectionloss exception. I was just curious why it occurred so often in my described scenario. I would have assumed that in that scenario it shouldn't occur at all, but it was almost half of the requests that returned with a connectionloss. Cheers, Michael > On Mon, Feb 1, 2010 at 4:30 AM, Michael Bauland > <michael.baul...@knipp.de>wrote: > >> Hello, >> >> I've got a question regarding the connectionloss exception thrown by Java. >> I've got an ensemble running with three zk servers. If one of the three >> servers is not running, the whole ensemble should still work (and it >> does, so that's fine). But in this situation I experience quite often a >> connectionloss exception and I'm wondering if I'm doing something wrong >> or if that's to be expected. >> >> My Code is rather simple: >> I create a new connection to my ensemble using >> >> ZooKeeper zk = new ZooKeeper (connectString, timeOut, new MyWatcher ()); >> >> where connectString contains all three servers. Then I use the ZooKeeper >> to read data from a certain path: >> >> zk.getData (path, false, null); >> >> This call quite often returns an exception like >> >> org.apache.zookeeper.KeeperException$ConnectionLossException: >> KeeperErrorCode = ConnectionLoss for /125/170/test >> >> But according to your documentation, the connectionloss exception should >> only occur in the following two cases: >> >>> 1. The application calls an operation on a session that is no longer >> alive/valid >> >> This should not be the case, since I only just created the session. >> >>> 2. The ZooKeeper client disconnects from a server when there are >> pending operations to that server, i.e., there is a pending asynchronous >> call. >> >> The should also not be the case. I was just doing a read request and no >> other client was accessing the ensemble. >> >> >> My only idea is that maybe the connection call first tried to connect to >> the zookeeper server that was not running (remember only two of the >> three servers are running) and before it had a chance to try to connect >> to one of the other servers, my getData call was made and failed with >> connectionloss. Could that be the reason? >> But I thought the connection handling was automatic and if a connection >> failed the client would automatically try any of the other listed >> servers without the user noticing!? >> >> Thanks for any help. >> >> Cheers, >> >> Michael >> >> >> -- >> Michael Bauland >> michael.baul...@knipp.de >> bauland.tel >> > > > -- Michael Bauland michael.baul...@knipp.de bauland.tel
