Tech note on the wiki? Or in the details section on the curator.apache.org?
On Thu, Mar 23, 2017 at 8:56 AM, Jordan Zimmerman < [email protected]> wrote: > Yeah, sorry, I meant point 3. People ask about connection handling all the > time. > > On Mar 22, 2017, at 4:55 PM, Cameron McKenzie <[email protected]> > wrote: > > Which bit in particular? > > Point 3 perhaps? I think that point 1 and 2 are probably already covered? > > On Thu, Mar 23, 2017 at 8:47 AM, Jordan Zimmerman < > [email protected]> wrote: > >> This would make a nice tech note on the wiki if anyone's up to it. >> >> -Jordan >> >> On Mar 22, 2017, at 4:13 PM, Cameron McKenzie <[email protected]> >> wrote: >> >> 1.) Calling close() will just clean up any resources associated with the >> CuratorFramework (Zookeeper connection's etc.). If your application exits >> without calling close(), this will not cause any issues. >> >> 2.) InterProcessMutex's are implemented using an ephemeral node in >> Zookeeper. If your client dies without releasing the mutex then this >> ephemeral node will be removed after the session times out. So, yes, after >> your specified session timeout other clients will be able to acquire the >> mutex. >> >> 3.) SUSPENDED occur as soon as the connection loss to ZK is determined. >> The LOST event differs depending on which version of Curator you're using. >> In Curator 2.x lost will occur once all of the retries have occurred (based >> on your specified retry policy). In Curator 3.x, Curator will simulate >> server side session loss, by starting a timer upon receiving the SUSPENDED >> event, and then publish a LOST event once the session timeout has been >> reached. >> >> The RECONNECTED event will occur once a connection has been reestablished >> to ZK. You can rely on Curator reconnecting when it is possible to do so. >> cheers >> >> On Thu, Mar 23, 2017 at 4:30 AM, Benson Qiu <[email protected]> wrote: >> >>> Hi, >>> >>> Several questions: >>> >>> 1. The CuratorFramework documentation >>> <http://curator.apache.org/curator-framework/> says that "should share >>> one CuratorFramework per ZooKeeper cluster in your application". I create >>> an instance and call CuratorFramework#start() on application startup and >>> reuse the same instance throughout the lifetime of my application, but I >>> never call CuratorFramework#close(). Is this bad practice? What happens if >>> my application periodically killed and restarted? >>> >>> 2. If I acquire an InterProcessMutex and my application is killed before >>> I call InterProcessMutex#release(), what happens? Based on my experiments >>> with TestingServer, it seems that after DEFAULT_SESSION_TIMEOUT_MS >>> <https://github.com/apache/curator/blob/022de3921a120c6f86cc6e21442327cc04b66cd2/curator-framework/src/main/java/org/apache/curator/framework/CuratorFrameworkFactory.java#L51>, >>> other applications are able to acquire the InterProcessMutex with the same >>> lock path. So there might be temporary starvation, but no deadlock. Is my >>> understanding correct? >>> >>> 3. I did a quick experiment where I pulled out my ethernet cable (lost >>> connection to the remote ZK cluster), waited several minutes, and then >>> inserted my ethernet cable in again. I observed from >>> ConnectionStateListener that the state will change to SUSPENDED, then LOST, >>> and when the ethernet cable is inserted again, RECONNECTED. How long does >>> it take for each state change to happen? Even if I lose connection for a >>> long period of time, can I trust that CuratorFramework will always handle >>> reconnecting? >>> >>> Any help, even if it's on a subset of these questions, would be really >>> appreciated! >>> >>> Thanks, >>> Benson >>> >> >> >> > >
