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https://issues.apache.org/jira/browse/ZOOKEEPER-4681?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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krystal he updated ZOOKEEPER-4681:
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Description:
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. My tool can isolate
the PROPOSAL, ACK and COMMIT messages and collect the values of some variables
of each server at the end of each round.
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 servers.
# Request to set /key0 to 1001 on 3 servers.
# Stop all servers and restart them.
# Check the contents of /key0 and /key1. Surprisingly, both requests
worked，reading /key0 == 1000, /key1 == 1001.
#
was:
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.
Initially, start an ensemble with 3 servers called A, B, and C, and initialize
2 znodes called /key0 and /key1 to 0.
> 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: Major
>
> 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. My tool can isolate
> the PROPOSAL, ACK and COMMIT messages and collect the values of some
> variables of each server at the end of each round.
> 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 servers.
> # Request to set /key0 to 1001 on 3 servers.
> # Stop all servers and restart them.
> # Check the contents of /key0 and /key1. Surprisingly, both requests
> worked，reading /key0 == 1000, /key1 == 1001.
> #
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