[GitHub] [helix] pkuwm commented on a change in pull request #1035: [WIP] Fix leaking Zk path watch and Callbackhandler issue

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

pkuwm commented on a change in pull request #1035:
URL: https://github.com/apache/helix/pull/1035#discussion_r431681552



##########
File path: zookeeper-api/src/main/java/org/apache/helix/zookeeper/api/client/RealmAwareZkClient.java
##########
@@ -71,10 +71,14 @@
   // listener subscription
   List<String> subscribeChildChanges(String path, IZkChildListener listener);
 
+  List<String> subscribeChildChanges(String path, IZkChildListener listener, boolean skipWatchingNodeNotExist);

Review comment:
       This is a public interface And HelixZkClient also extends it, do we need a default implementation for backward compatibility?

##########
File path: zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/ZkClient.java
##########
@@ -257,12 +274,22 @@ public void subscribeDataChanges(String path, IZkDataListener listener) {
         }
       }
     }
-    watchForData(path);
+

Review comment:
       Agreed. Maybe we could do this: add listeners first. If watch fails, we remove listeners?

##########
File path: zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/ZkClient.java
##########
@@ -1270,6 +1325,9 @@ public void deleteRecursively(String path) throws ZkClientException {
   private void processDataOrChildChange(WatchedEvent event, long notificationTime) {
     final String path = event.getPath();
     final boolean pathExists = event.getType() != EventType.NodeDeleted;
+    if (EventType.NodeDeleted == event.getType()) {
+      LOG.info("event delelete:" + event.getPath());

Review comment:
       Is this log necessary? May pollute the logs?

##########
File path: zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/ZkClient.java
##########
@@ -1858,24 +1923,47 @@ public Object call() throws Exception {
     });
   }
 
+  private boolean watchForData(final String path, boolean skipWatchingNodeNotExist) {
+    try {
+      if (skipWatchingNodeNotExist) {
+        Stat stat = new Stat();

Review comment:
       No need to get stat? Passing null is enough.




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