[ZOOKEEPER-4005] Zookeeper will not sync snapshot while get DIFF and cause start failed.

• Type: Bug
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.5.1, 3.5.6
• Component/s: server
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: doupengwei
• Created: 18/Nov/20 09:18
• Updated: 22/Feb/21 01:25

Description

The  version 3.5.1 of ZK does not detect whether the snapshot file exists or not. However, the snapshot file detection is added in the subsequent version. When I tested the upgrade from 3.5.1 to 3.5.6, I found that after the completion of ZK election, One of the ZK node has an error in the following phase due to some network reasons, and then it will receive a diff reply. At this time,  both snapshotNeeded and isPreZAB1_0 （   Learner#syncWithLeader(long newLeaderZxid)  ）are assigned to false.  So, none of snapshot file will be generated but a log file, which will cause the startup failure after the upgrade. 

 

 

 

Issue Links

• is related to: ZOOKEEPER-3056 Fails to load database with missing snapshot file but valid transaction log file
• links to: GitHub Pull Request #1548