[CASSANDRA-15350] Separate exceptions for CAS write timeout exceptions caused by contention and unknown result

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0-alpha4, 4.0
• Component/s: Feature/Lightweight Transactions
• Labels: protocolv5 pull-request-available
• Change Category: Operability
• Complexity: Normal
• Platform: All
• Impacts: Clients

Source Control Link

https://github.com/apache/cassandra/commit/d3b3dcbb353de97220a11f55391babf149410905

Test and Documentation Plan

Unit tests + (possibly) fuzz tests?

• Assignee: Yifan Cai
• Reporter: Alex Petrov

Authors

Yifan Cai

Reviewers

Alex Petrov, Dinesh Joshi

• Created: 09/Oct/19 15:52
• Updated: 30/Jan/24 15:04
• Resolved: 03/Feb/20 13:58

Description

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.

Issue Links

• is duplicated by: CASSANDRA-9330 CAS timeout errors should use a different exception than WriteTimeoutException as WTE can happen when nodes fail to respond.
• is duplicated by: CASSANDRA-7822 Confusing timeout on CAS contention
• relates to: CASSANDRA-9328 WriteTimeoutException thrown when LWT concurrency > 1, despite the query duration taking MUCH less than cas_contention_timeout_in_ms
• links to: GitHub Pull Request #379