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Posted to commits@cassandra.apache.org by "Yifan Cai (Jira)" <ji...@apache.org> on 2020/01/31 21:42:00 UTC
[jira] [Comment Edited] (CASSANDRA-15350) Add CAS “uncertainty” and “contention" messages that are currently propagated as a WriteTimeoutException.
[ https://issues.apache.org/jira/browse/CASSANDRA-15350?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17027827#comment-17027827 ]
Yifan Cai edited comment on CASSANDRA-15350 at 1/31/20 9:41 PM:
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Thanks Alex.
Using fuzz to reproduce contentions sounds OK to me.
Having deterministic test cases to precisely produce contentions is also valuable, IMO. But I am good to not have those test cases being merged as of now.
I rebased my branch with your improvements commit and added/tweaked test cases in {{CasWriteTest}}.
Still the same [PR|https://github.com/apache/cassandra/pull/379] and [code branch|https://github.com/yifan-c/cassandra/tree/cas-exception-changes]. Test result is [here.|https://app.circleci.com/github/yifan-c/cassandra/pipelines/8d10bf4b-9f36-468e-922c-18a6dcf7df81/workflows/d20b5ae8-cd82-49cb-9026-97644359ee76]
was (Author: yifanc):
Thanks Alex.
Using fuzz to reproduce contentions sounds OK to me.
Having deterministic test cases to precisely produce contentions is also valuable, IMO. But I am good to not have those test cases being merged as of now.
I rebased my branch with your improvements commit and added/tweaked test cases in {{CasWriteTest}}.
Still the same [PR|https://github.com/apache/cassandra/pull/379] and [code branch|https://github.com/yifan-c/cassandra/tree/cas-exception-changes]. Test result is [here.|https://app.circleci.com/github/yifan-c/cassandra/pipelines/458cafcb-117b-443a-ae6c-c089efd6a929/workflows/7742c20d-1a82-47a8-93d0-cc40a542db5f]
> Add CAS “uncertainty” and “contention" messages that are currently propagated as a WriteTimeoutException.
> ---------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-15350
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15350
> Project: Cassandra
> Issue Type: Improvement
> Components: Feature/Lightweight Transactions
> Reporter: Alex Petrov
> Assignee: Yifan Cai
> Priority: Normal
> Labels: protocolv5, pull-request-available
> Attachments: Utf8StringEncodeBench.java
>
> Time Spent: 20m
> Remaining Estimate: 0h
>
> Right now, CAS uncertainty introduced in https://issues.apache.org/jira/browse/CASSANDRA-6013 is propagating as WriteTimeout. One of this conditions it manifests is when there’s at least one acceptor that has accepted the value, which means that this value _may_ still get accepted during the later round, despite the proposer failure. Similar problem happens with CAS contention, which is also indistinguishable from the “regular” timeout, even though it is visible in metrics correctly.
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