Some kinds of membership changes will still cause overcounts
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Key: CASSANDRA-1961
URL: https://issues.apache.org/jira/browse/CASSANDRA-1961
Project: Cassandra
Issue Type: Bug
Components: Core
Reporter: Stu Hood
Fix For: 0.8
Assume replicas A, B, C, and a joining node D, where D is joining between A and
B. The join process will remove C from the replica set, but C will still be
holding counts for those replicas (unless cleanup is run, which we can't safely
assume). If a second membership change occurs such that any of A, B or D leave
the ring, C will be acting as a new member of the replica set, but it will
still be holding its old counts.
The join will:
* BOOTSTRAP - D will bootstrap from the nearest replica, possibly C (but not
necessarily)
The leave will either:
* UNBOOTSTRAP - D will send to C
* RESTORE_REPLICA_COUNT - since D is assumed dead, C will stream from the
nearest replica
Only the AES stream task performs fixups of counters: in all other cases I
think we assume that 'nodetool cleanup' has run, so it is possible to overcount.
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