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  1. ZooKeeper
  2. ZOOKEEPER-2368

Client watches are not disconnected on close

    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 3.4.0, 3.5.0
    • Fix Version/s: 3.6.0, 3.5.5
    • Component/s: None

      Description

      If I have a ZooKeeper client connected to an ensemble then obviously I can register watches.

      If the client is disconnected (for example by a failing ensemble member) then I get a disconnection event for all of my watches. If, on the other hand, my client is closed then I do not get a disconnection event. This asymmetry makes it really hard to clear up properly when using the asynchronous API, as there is no way to "fail" data reads/updates when the client is closed.

      I believe that the correct behaviour should be for all watchers to receive a disconnection event when the client is closed. The watchers can then respond as appropriate, and can differentiate between a "server disconnect" and a "client disconnect" by checking the ZooKeeper#getState() method.

      This would not be a breaking behaviour change as Watchers are already required to handle disconnection events.

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              • Assignee:
                timothyjward Timothy Ward
                Reporter:
                timothyjward Timothy Ward
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