kaisun2000 commented on a change in pull request #1119:
URL: https://github.com/apache/helix/pull/1119#discussion_r455230676
##########
File path:
zookeeper-api/src/main/java/org/apache/helix/zookeeper/zkclient/ZkClient.java
##########
@@ -1221,20 +1237,109 @@ private void reconnect() {
}
}
+ private class SyncCallbackHandler extends ZkAsyncCallbacks.DefaultCallback
implements AsyncCallback.VoidCallback {
+ private String _sessionId;
+
+ SyncCallbackHandler(String sessionId) {
+ _sessionId = sessionId;
+ }
+
+ @Override
+ public void processResult(int rc, String path, Object ctx) {
+ LOG.info("sycnOnNewSession with sessionID {} async return code: {}",
_sessionId, rc);
+ callback(rc, path, ctx);
+ }
+
+ @Override
+ public void handle() {
+ // Make compiler happy, not used.
+ }
+
+ @Override
+ protected boolean needRetry(int rc) {
+ try {
+ switch (KeeperException.Code.get(rc)) {
+ /** Connection to the server has been lost */
+ case CONNECTIONLOSS:
+ return true;
+ default:
+ return false;
+ }
+ } catch (ClassCastException | NullPointerException ex) {
+ LOG.error("Session {} failed to handle unknown return code {}. Skip
retrying. ex {}",
+ _sessionId, rc, ex);
+ return false;
+ }
+ }
+ }
+
+ private void doAsyncSync(final ZooKeeper zk, final String path, final long
startT,
+ final SyncCallbackHandler cb) {
+ zk.sync(path, cb,
+ new ZkAsyncRetryCallContext(_asyncCallRetryThread, cb, _monitor,
startT, 0, false) {
+ @Override
+ protected void doRetry() throws Exception {
+ doAsyncSync(zk, path, startT, cb);
+ }
+ });
+ }
+
+ private boolean retrySync(String sessionId) throws ZkInterruptedException {
+ if (!_syncOnNewSession) {
+ return true;
+ }
+
+ SyncCallbackHandler callbackHandler = new SyncCallbackHandler(sessionId);
+
+ final ZkConnection zkConnection = (ZkConnection) getConnection();
Review comment:
> 1. We need to check the session Id after you get the zk object. If
session does not match then skip the operation.
The first ZooKeeper object extracted from connection (line 1259) is up in
the stack in processStateChange() and then passed into doAsync(). Note,
procesStateChange() is inside the lock of getEventLock(). I think under the
lock, there is not possibility of changing another ZooKeeper object of
different session, right? So this is not a concern in this case.
> 2. You might want to try-catch the line 1260 since if the zk already
becomes invalid at the first call, it might throw an exception and we can just
return false.
See the reply above. Am I missing something here? Can you give an example?
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