[CASSANDRA-12489] consecutive repairs of same range always finds 'out of sync' in sane cluster

• Type: Bug
• Status: Open
• Priority: Normal
• Resolution: Unresolved
• Component/s: Legacy/Streaming and Messaging
• Labels: lhf
• Severity: Normal
• Complexity: Low Hanging Fruit
• Assignee: Benjamin Roth
• Reporter: Benjamin Roth

Authors

Benjamin Roth

• Created: 18/Aug/16 08:07
• Updated: 13/Jun/19 18:28

Description

No matter how often or when I run the same subrange repair, it ALWAYS tells me that some ranges are our of sync. Tested in 3.9 + 3.10 (git trunk of 2016-08-17). The cluster is sane. All nodes are up, cluster is not overloaded.
I guess this is not a desired behaviour. I'd expect that a repair does what it says and a consecutive repair shouldn't report "out of syncs" any more if the cluster is sane.
Especially for tables with MVs that puts a lot of pressure during repair as ranges are repaired over and over again.

See traces of different runs attached.

Issue Links

• relates to: CASSANDRA-12730 Thousands of empty SSTables created during repair - TMOF death
• relates to: CASSANDRA-12888 Incremental repairs broken for MVs and CDC