https://cwiki.apache.org/confluence/display/CURATOR/TN12
On Thu, Mar 23, 2017 at 9:17 AM, Cameron McKenzie <mckenzie....@gmail.com> wrote: > Ok, I will add a tech note to the wiki. > cheers > > On Thu, Mar 23, 2017 at 9:16 AM, Jordan Zimmerman < > jor...@jordanzimmerman.com> wrote: > >> My vote is the wiki - that way we can update it, etc. >> >> -JZ >> >> >> On Mar 22, 2017, at 5:15 PM, Cameron McKenzie <mckenzie....@gmail.com> >> wrote: >> >> 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 < >> jor...@jordanzimmerman.com> 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 <mckenzie....@gmail.com> >>> 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 < >>> jor...@jordanzimmerman.com> 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 <cammcken...@apache.org> >>>> 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 <qiu.ben...@gmail.com> >>>> 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 >>>>> >>>> >>>> >>>> >>> >>> >> >> >
