[ https://issues.apache.org/jira/browse/ZOOKEEPER-4681?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
krystal he updated ZOOKEEPER-4681: ---------------------------------- Attachment: (was: zookeeper-divergence2.log) > Uncommitted requests have been executed > ---------------------------------------- > > Key: ZOOKEEPER-4681 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-4681 > Project: ZooKeeper > Issue Type: Bug > Components: quorum > Affects Versions: 3.5.8 > Reporter: krystal he > Priority: Critical > > Using a [tool|https://github.com/kry4tall/CC-ZOO358] that I modifyed from > [Filip Niksic's zootester|https://github.com/fniksic/zootester] for testing > ZooKeeper, I discovered the following scenario which causes uncommitted > requests to be executed. > Zab protocol has three rounds: PROPOSE, ACK, and COMMIT. By adding relevant > code to the zookeeper source code,my tool can drop the PROPOSAL, ACK and > COMMIT messages and collect the values of some variables of each server at > the end of each round. Except affecting message reception, my code will not > affect other actions of Zookeeper. > > Setup: > Replace directory called "zookeeper-server" in Zookeeper 3.5.8 with the > "zookeeper-server" in [my github repo|https://github.com/kry4tall/CC-ZOO358]. > Ant the modified Zookeeper 3.5.8 to get zookeeper-3.5.8.jar. Replace > zookeeper-3.5.8.jar downloaded by maven. > Create a directory called "states" and a file called > "[scenarios|https://github.com/kry4tall/CC-ZOO358/blob/krystal/zoo-tester/test/scenarios]". > Write the path to test.properties in zoo-tester's resource directory. > Use "-s divergence-2" as the startup parameter to run the main method of > ZooTester. > OS: ubuntu 22.04.2. > > Base scenario: > Initially, start an ensemble with 3 servers called A, B, and C, and > initialize 2 znodes called /key0 and /key1, and set them to 0 and 1 > respectively. > # Request to set /key0 to 1000 on 3 servers. > # Isolate the ack messages of 2 followers. > # (Optional) Read /key0 and /key1. > # Request to set /key0 to 1001 on 3 servers. > # (Optional) Read /key0 and /key1. > Surprisingly, both requests worked,reading /key0 == 1000, /key1 == 1001 from > C and /key0 == 0, /key1 == 1001 from A,B. > However, value 1000 and 1001 should not appear in any znode, because the > proposal of the first request cannot obtain enough ack, it cannot be > committed. And servers will also not commit the proposal of the second > request, because there is a pending proposal that has not been committed > before, according to the source code of Zookeeper. -- This message was sent by Atlassian Jira (v8.20.10#820010)