[GitHub] [zookeeper] hanm commented on a change in pull request #1445: ZOOKEEPER-3911: Data inconsistency caused by DIFF sync uncommitted log

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

hanm commented on a change in pull request #1445:
URL: https://github.com/apache/zookeeper/pull/1445#discussion_r483361109



##########
File path: zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/Learner.java
##########
@@ -741,18 +741,30 @@ protected void syncWithLeader(long newLeaderZxid) throws Exception {
                     }
 
                     self.setCurrentEpoch(newEpoch);
-                    writeToTxnLog = true; //Anything after this needs to go to the transaction log, not applied directly in memory
+                    writeToTxnLog = true;
+                    //Anything after this needs to go to the transaction log, not applied directly in memory
                     isPreZAB1_0 = false;
+
+                    // ZOOKEEPER-3911: make sure sync the uncommitted logs before commit them (ACK NEWLEADER).
+                    sock.setSoTimeout(self.tickTime * self.syncLimit);
+                    self.setSyncMode(QuorumPeer.SyncMode.NONE);
+                    zk.startup();

Review comment:
       This is possible but unfortunately there is no way afaik to persist the proposals without staring the server in first place. The better approach is to provide a control API (such as ZooKeeperServer#startServing) so we can control when requests will be allowed to come regardless of the servers state (running or not). Maybe there is already such an API / approach but I need sometime to figure this out.




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org