[
https://issues.apache.org/jira/browse/CASSANDRA-20514?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Brandon Williams updated CASSANDRA-20514:
-----------------------------------------
Fix Version/s: 4.1.9
5.0.4
5.1
(was: 5.x)
(was: 4.1.x)
(was: 5.0.x)
> Paxos mixed mode infinite loop with ttl'd state
> -----------------------------------------------
>
> Key: CASSANDRA-20514
> URL: https://issues.apache.org/jira/browse/CASSANDRA-20514
> Project: Apache Cassandra
> Issue Type: Bug
> Components: Feature/Lightweight Transactions
> Reporter: Blake Eggleston
> Assignee: Blake Eggleston
> Priority: Normal
> Fix For: 4.1.9, 5.0.4, 5.1
>
>
> This is similar to the bug fixed in CASSANDRA-20493.
> CEP-14 changed the ttl behavior of legacy paxos state to expire based off the
> ballot time of the operation being persisted, not the time a commit is
> persisted. This eliminated the race addressed by CASSANDRA-12043, and so the
> check it added to the most recent commit prepare logic was removed.
> When operating in mixed mode though, this race can still be a problem. If a
> 4.1 or higher node is coordinating a paxos operation with 2 or more replicas
> on 4.0 or lower, this race becomes a problem again. You need 3 things to make
> this an infinite loop
> 1. a 4.1 node coordinating a paxos operation with 2x 4.0 replicas
> 2. replica A) a 4.0 node returns a most recent commit for a ballot that's
> could have been ttld
> 3. replica B) a 4.0 node has ttl'd that mrc AND converted the ttld cells into
> tombstones
> The 4.1 coordinator receives the mrc from replica A, but since it no longer
> disregards missing most recent commits past the ttl window, it sends the
> "missing" commit to replica B. Since replica B now has a tombstone for that
> mrc, and tombstones win when reconciled with live cells, even ones with ttls,
> the commit is a noop and it continues to report nothing for its mrc value
> when the coordinator restarts the prepare phase. This loops until the query
> times out
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
