> Function addColumn at class SuperColumn tries to atomically add a column to > the concurrent collection “columns_” using the following code:
Deletions in Cassandra involve an insertion of a tombstone rather than actual column deletion. In the case of this bit of code, I believe, and I am not speaking authoritatively, the removal only happens in (1) the read path when filtering results (on presumably query-local data) and (2) during compaction (on presumably compaction-local data). I did browse through the various callers which seemed to confirm that this was the case. In other words, I do not believe the remove() code path should not ever be taken concurrently with insertions (by design, and not by accident). Anyone care to confirm/deny? -- / Peter Schuller
