[GitHub] [pulsar] coderzc opened a new pull request, #18234: [fix][broker][branch-2.8] Fix watcher count on ZK increasing indefinitely

[GitBox <gi...@apache.org>]

coderzc opened a new pull request, #18234:
URL: https://github.com/apache/pulsar/pull/18234

   ### Motivation
   
   I find some z-node only call `exist` and add watcher, but `ExistsWatchRegistration` still will be registered even though the z-node may never be created. this will lead to the watcher count on ZK increasing indefinitely.
   
   ```java
       /** Handle the special case of exists watches - they add a watcher
        * even in the case where NONODE result code is returned.
        */
       class ExistsWatchRegistration extends WatchRegistration {
   
           public ExistsWatchRegistration(Watcher watcher, String clientPath) {
               super(watcher, clientPath);
           }
   
           @Override
           protected Map<String, Set<Watcher>> getWatches(int rc) {
               return rc == 0 ? watchManager.dataWatches : watchManager.existWatches;
           }
   
           @Override
           protected boolean shouldAddWatch(int rc) {
               return rc == 0 || rc == KeeperException.Code.NONODE.intValue();
           }
   
       }
   ```
   
   ### Modifications
   
   Remove watcher if `exist` return `NONODE`.
   Remove unused method in ZkUtils.
   
   ### Documentation
   
   <!-- DO NOT REMOVE THIS SECTION. CHECK THE PROPER BOX ONLY. -->
   
   - [ ] `doc` <!-- Your PR contains doc changes. Please attach the local preview screenshots (run `sh start.sh` at `pulsar/site2/website`) to your PR description, or else your PR might not get merged. -->
   - [ ] `doc-required` <!-- Your PR changes impact docs and you will update later -->
   - [x] `doc-not-needed` <!-- Your PR changes do not impact docs -->
   - [ ] `doc-complete` <!-- Docs have been already added -->
   
   ### Matching PR in forked repository
   
   PR in forked repository: 
   


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[GitHub] [pulsar] coderzc closed pull request #18234: [fix][broker][branch-2.8] Fix watcher count on ZK increasing indefinitely

[GitBox <gi...@apache.org>]

coderzc closed pull request #18234: [fix][broker][branch-2.8] Fix watcher count on ZK increasing indefinitely
URL: https://github.com/apache/pulsar/pull/18234


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