[jira] [Created] (CASSANDRA-14543) Hinted handoff to replay purgeable tombstones

["Jay Zhuang (JIRA)" <ji...@apache.org>]

Jay Zhuang created CASSANDRA-14543:
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             Summary: Hinted handoff to replay purgeable tombstones 
                 Key: CASSANDRA-14543
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-14543
             Project: Cassandra
          Issue Type: Improvement
            Reporter: Jay Zhuang


Hinted-handoff currently only dispatches and applies the mutations that are within GCGS: [{{Hint.java:97}}|https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/hints/Hint.java#L97]. Which is to make sure it won't resurrect any deleted data.

But replaying tombstones should be safe, it could reduce the chance to have [un-repairable inconsistent data|https://lists.apache.org/thread.html/2d3d39d960143d4d2146ed2530821504ff855e832713dec7d0afd8ac@%3Cdev.cassandra.apache.org%3E].

Here is the user scenario it tries to fix:
{noformat}
1. Create a 3 nodes cluster
2. Create a table with small gc_grace_seconds (for reproducing purpose):

CREATE KEYSPACE foo WITH replication = {'class': 'SimpleStrategy',
'replication_factor': 3};
CREATE TABLE foo.bar (
id int PRIMARY KEY,
name text
) WITH gc_grace_seconds=30;

3. Insert data with consistency all:

INSERT INTO foo.bar (id, name) VALUES(1, 'cstar');

4. stop 1 node

$ ccm node2 stop

5. Delete the data with consistency quorum:

DELETE FROM foo.bar WHERE id=1;

6. Wait 30 seconds and then start node2:

$ ccm node2 start
{noformat}
Now, node2 has the data, node1/node3 have the purgeable tombstone. It triggers RR every time which sends data from node2 to node1/node3 but repairs nothing.
With purgeable tombstones hints handoff, it at least will dispatch the tombstone and delete the data on node2. It won't fix the root cause but reduce the chance to have this issue.



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