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Jacky007 commented on ZOOKEEPER-1675: ------------------------------------- Sorry, it has nothing to do with correctness. What I want to tell is we may need more codes to achieve a really "strong read". > Make sync a quorum operation > ---------------------------- > > Key: ZOOKEEPER-1675 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1675 > Project: ZooKeeper > Issue Type: Bug > Affects Versions: 3.4.0, 3.5.0 > Reporter: Alexander Shraer > > sync + read is supposed to return at least the latest write that completes > before the sync starts. This is true if the leader doesn't change, but when > it does it may not work. The problem happens when the old leader L1 still > thinks that it is the leader but some other leader L2 was already elected and > committed some operations. Suppose that follower F is connected to L1 and > invokes a sync. Even though L1 responds to the sync, the recent operations > committed by L2 will not be flushed to F so a subsequent read on F will not > see these operations. > To prevent this we should broadcast the sync like updates. > This problem is also mentioned in Section 4.4 of the ZooKeeper peper (but the > proposed solution there is insufficient to solve the issue). -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira