[ https://issues.apache.org/jira/browse/CASSANDRA-7764?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14096084#comment-14096084 ]
Jeremiah Jordan commented on CASSANDRA-7764: -------------------------------------------- bq. I like that idea, though it won't help if they don't run it True, but it does solve the problem of: bq. It's definitely not a best practice for data integrity. So the people who know they should be running it, but aren't because throwing away data scares them, could now run cleanup. > RFC: Range movements will "wake up" previously invisible data > ------------------------------------------------------------- > > Key: CASSANDRA-7764 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7764 > Project: Cassandra > Issue Type: Bug > Reporter: Rick Branson > > Presumably this has been going on as long as Cassandra has existed, but > wanted to capture it here since it came up in an IRC discussion. This issue > will probably show up on any cluster eventually. > Scenario: > 1) Start with a 3-node cluster, RF=1 > 2) A 4th node is added to the cluster > 3) Data is deleted on ranges belonging to 4th node > 4) Wait for GC to clean up some tombstones on 4th node > 4) 4th node removed from cluster > 5) Deleted data will reappear since it was dormant on the original 3 nodes > This could definitely happen in many other situations where dormant data > could exist such as inconsistencies that aren't resolved before range > movement, but the case above seemed the most reasonable to propose as a > real-world problem. > The cleanup operation can be used to get rid of the dormant data, but from my > experience people don't run cleanup unless they're low on disk. It's > definitely not a best practice for data integrity. -- This message was sent by Atlassian JIRA (v6.2#6252)