[ https://issues.apache.org/jira/browse/CASSANDRA-19365?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Caleb Rackliffe updated CASSANDRA-19365: ---------------------------------------- Reviewers: Caleb Rackliffe, Maxim Muzafarov, Piotr Kolaczkowski, Caleb Rackliffe (was: Caleb Rackliffe, Maxim Muzafarov, Piotr Kolaczkowski) Caleb Rackliffe, Maxim Muzafarov, Piotr Kolaczkowski, Caleb Rackliffe (was: Caleb Rackliffe, Maxim Muzafarov, Piotr Kolaczkowski) Status: Review In Progress (was: Patch Available) > invalid EstimatedHistogramReservoirSnapshot::getValue values due to race > condition in DecayingEstimatedHistogramReservoir > ------------------------------------------------------------------------------------------------------------------------- > > Key: CASSANDRA-19365 > URL: https://issues.apache.org/jira/browse/CASSANDRA-19365 > Project: Cassandra > Issue Type: Bug > Components: Observability/Metrics > Reporter: Jakub Zytka > Assignee: Maxim Muzafarov > Priority: Normal > Fix For: 4.0.x, 4.1.x, 5.0.x, 5.x > > Time Spent: 3.5h > Remaining Estimate: 0h > > `DecayingEstimatedHistogramReservoir` has a race condition between `update` > and `rescaleIfNeeded`. > A sample which ends up (`update`) in an already scaled decayingBucket > (`rescaleIfNeeded`) may still use a non-scaled weight because `decayLandmark` > has not been updated yet at the moment of `update`. > > The observed consequence was flooding of the cluster with speculative retries > (we happened to hit low-percentile buckets with overweight samples, which > drove p99 below true p50 for a long time). > Please note that despite the manifestation being similar to CASSANDRA-19330, > these are two distinct bugs in their own right. > This bug affects versions 4.0+ > On 3.11 there's locking in DEHR. I did not check earlier versions. -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org