[CASSANDRA-18905] Index.Group is incorrectly unregistered from the SecondaryIndexManager

• Type: Bug
• Status: Resolved
• Priority: Urgent
• Resolution: Fixed
• Fix Version/s: 5.0-alpha2, 5.0, 5.1
• Component/s: Feature/2i Index
• Epic Link: Storage Attached Indexes (Phase 2)
• Bug Category: Availability - Process Crash
• Severity: Critical
• Complexity: Low Hanging Fruit
• Discovered By: Performance Regression Test
• Platform: All
• Since Version: 5.0-alpha1

Source Control Link

https://github.com/apache/cassandra/commit/e45c1092f91edd63591f562b2120ea6a5fd3edd5

Test and Documentation Plan

CircleCI builds are included in the first comment.

• Assignee: Mike Adamson
• Reporter: Mike Adamson

Authors

Mike Adamson

Reviewers

Caleb Rackliffe, Zhao Yang

• Created: 04/Oct/23 09:49
• Updated: 19/Oct/23 12:09
• Resolved: 18/Oct/23 19:43

Description

An Index.Group is removed from the SecondaryIndexManager during unregisterIndex if it contains no indexes after the index is unregistered.

The code for removing the group uses the wrong key to remove the group from the indexGroups map. It is using the group object rather than the group name that is used as the key in the map.

This means that the group is not added again if a new index is registered using that group. The knock on from this is that the StorageAttachedIndexGroup unregisters itself from the Tracker when it has no indexes after an index is removed. The same group with no tracker is then used for new indexes. This group then receives no notifications about sstable or memtable updates. The ultimate side effect of this is that, memtables are not released, resulting in memory leaks and indexes are not updated with new sstables and their associated index files.

Issue Links

• Testing discovered: CASSANDRA-18944 Test failure: org.apache.cassandra.simulator.test.ShortPaxosSimulationTest.simulationTest