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ZOOKEEPER-4472: Remove persistent watches individually #2006

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Merged
tisonkun merged 3 commits into from
Jun 15, 2023
Merged

ZOOKEEPER-4472: Remove persistent watches individually #2006

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83d3ea9
ZOOKEEPER-4472: Remove persistent watches individually
kezhuw Jun 10, 2023
148b212
Assert removing WatcherType::Data from AddWatchMode::Persistent is im…
kezhuw Jun 14, 2023
7498a85
fixup! Assert removing WatcherType::Data from AddWatchMode::Persisten…
kezhuw Jun 14, 2023
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7 changes: 6 additions & 1 deletion zookeeper-server/src/main/java/org/apache/zookeeper/Watcher.java
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Original file line number Diff line number Diff line change
Expand Up @@ -191,6 +191,8 @@ public static EventType fromInt(int intValue) {
enum WatcherType {
Children(1),
Data(2),
Persistent(4),
PersistentRecursive(5),
Any(3);

// Integer representation of value
Expand All @@ -212,7 +214,10 @@ public static WatcherType fromInt(int intValue) {
return WatcherType.Data;
case 3:
return WatcherType.Any;

case 4:
return Persistent;
case 5:
return PersistentRecursive;
default:
throw new RuntimeException("Invalid integer value for conversion to WatcherType");
}
Expand Down
40 changes: 20 additions & 20 deletions zookeeper-server/src/main/java/org/apache/zookeeper/ZKWatchManager.java
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Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,18 @@ public Map<Watcher.Event.EventType, Set<Watcher>> removeWatcher(
}
break;
}
case Persistent: {
synchronized (persistentWatches) {
removedWatcher = removeWatches(persistentWatches, watcher, clientPath, local, rc, persistentWatchersToRem);
}
break;
}
case PersistentRecursive: {
synchronized (persistentRecursiveWatches) {
removedWatcher = removeWatches(persistentRecursiveWatches, watcher, clientPath, local, rc, persistentWatchersToRem);
}
break;
}
case Any: {
synchronized (childWatches) {
removedWatcher = removeWatches(childWatches, watcher, clientPath, local, rc, childWatchersToRem);
Expand Down Expand Up @@ -225,18 +237,6 @@ void containsWatcher(String path, Watcher watcher, Watcher.WatcherType watcherTy
synchronized (childWatches) {
containsWatcher = contains(path, watcher, childWatches);
}

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@tisonkun tisonkun Jun 13, 2023

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I agree on this direction that it delivers more reasonable behaviors. But it can somehow still a user-facing manner changes. Maybe we need a release note to describe it.

I'll check the final logic tomorrow and give a review result :D

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@kezhuw kezhuw Jun 14, 2023

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Here are my findings:

  • containsWatcher is package private and used solely by ZKWatchManager::removeWatcher.
  • removeWatcher enforces more stringent NoWatcherException check than containsWatcher.

So, we are in lucking path that partially removing WatcherType::Data from AddWatchMode::Persistent is an error even it is permitted by server side(a.k.a rc is 0) and containsWatcher.

I pushed a test commit for this. I also pushed tests in kezhuw@8c35fce before ZOOKEEPER-4466. All these tests result in NOWATCHER when removing WatcherType::Data from AddWatchMode::Persistent.

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@kezhuw kezhuw Jun 14, 2023

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I have add "Release Note" to ZOOKEEPER-4466, ZOOKEEPER-4471 and ZOOKEEPER-4472.

Is that sufficient for us ? @eolivelli @tisonkun @anmolnar

synchronized (persistentWatches) {
boolean contains_temp = contains(path, watcher,
persistentWatches);
containsWatcher |= contains_temp;
}

synchronized (persistentRecursiveWatches) {
boolean contains_temp = contains(path, watcher,
persistentRecursiveWatches);
containsWatcher |= contains_temp;
}
break;
}
case Data: {
Expand All @@ -248,17 +248,17 @@ void containsWatcher(String path, Watcher watcher, Watcher.WatcherType watcherTy
boolean contains_temp = contains(path, watcher, existWatches);
containsWatcher |= contains_temp;
}

break;
}
case Persistent: {
synchronized (persistentWatches) {
boolean contains_temp = contains(path, watcher,
persistentWatches);
containsWatcher |= contains_temp;
containsWatcher |= contains(path, watcher, persistentWatches);
}

break;
}
case PersistentRecursive: {
synchronized (persistentRecursiveWatches) {
boolean contains_temp = contains(path, watcher,
persistentRecursiveWatches);
containsWatcher |= contains_temp;
containsWatcher |= contains(path, watcher, persistentRecursiveWatches);
}
break;
}
Expand Down
6 changes: 6 additions & 0 deletions zookeeper-server/src/main/java/org/apache/zookeeper/cli/RemoveWatchesCommand.java
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,8 @@ public class RemoveWatchesCommand extends CliCommand {
static {
options.addOption("c", false, "child watcher type");
options.addOption("d", false, "data watcher type");
options.addOption("p", false, "persistent watcher type");
options.addOption("r", false, "persistent recursive watcher type");
options.addOption("a", false, "any watcher type");
options.addOption("l", false, "remove locally when there is no server connection");
}
Expand Down Expand Up @@ -70,6 +72,10 @@ public boolean exec() throws CliWrapperException, MalformedPathException {
wtype = WatcherType.Children;
} else if (cl.hasOption("d")) {
wtype = WatcherType.Data;
} else if (cl.hasOption("p")) {
wtype = WatcherType.Persistent;
} else if (cl.hasOption("r")) {
wtype = WatcherType.PersistentRecursive;
} else if (cl.hasOption("a")) {
wtype = WatcherType.Any;
}
Expand Down
20 changes: 18 additions & 2 deletions zookeeper-server/src/main/java/org/apache/zookeeper/server/DataTree.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1563,11 +1563,16 @@ public boolean containsWatcher(String path, WatcherType type, Watcher watcher) {
case Data:
containsWatcher = this.dataWatches.containsWatcher(path, watcher, WatcherMode.STANDARD);
break;
case Persistent:
containsWatcher = this.dataWatches.containsWatcher(path, watcher, WatcherMode.PERSISTENT);
break;
case PersistentRecursive:
containsWatcher = this.dataWatches.containsWatcher(path, watcher, WatcherMode.PERSISTENT_RECURSIVE);
break;
case Any:
if (this.childWatches.containsWatcher(path, watcher, null)) {
containsWatcher = true;
}
if (this.dataWatches.containsWatcher(path, watcher, null)) {
} else if (this.dataWatches.containsWatcher(path, watcher, null)) {
containsWatcher = true;
}
break;
Expand All @@ -1584,6 +1589,17 @@ public boolean removeWatch(String path, WatcherType type, Watcher watcher) {
case Data:
removed = this.dataWatches.removeWatcher(path, watcher, WatcherMode.STANDARD);
break;
case Persistent:
if (this.childWatches.removeWatcher(path, watcher, WatcherMode.PERSISTENT)) {
removed = true;
}
if (this.dataWatches.removeWatcher(path, watcher, WatcherMode.PERSISTENT)) {
removed = true;
}
break;
case PersistentRecursive:
removed = this.dataWatches.removeWatcher(path, watcher, WatcherMode.PERSISTENT_RECURSIVE);
break;
case Any:
if (this.childWatches.removeWatcher(path, watcher, null)) {
removed = true;
Expand Down
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