I have a problem or at least something that I have missed to understand regarding commit log removal. I'm running cassandra 1.0.1 but have seen the same "thing" in 1.0. I thought that when a node is flushed or drained, it's memtable is flushed to disk and the commit log is removed and new commit logs are created as write requests comes in. I've setup a small test, adding column family data through cassandra-cli then running both flush and drain but the commit log isn't removed. There is only one commit log in the commit log directory. I've turned on debug and the log always reports "Not safe to delete...":
DEBUG [COMMIT-LOG-WRITER] 2011-11-01 20:51:19,195 CommitLog.java (line 458) discard completed log segments for ReplayPosition(segmentId=1320176934665, position=340), column family 7. DEBUG [COMMIT-LOG-WRITER] 2011-11-01 20:51:19,196 CommitLog.java (line 497) Not safe to delete commit log CommitLogSegment(/var/lib/cassandra/commitlog/CommitLog-1320176934665.log); dirty is ; hasNext: false Could someone please clarify the relationship between commit log creation, removal/rotation and flush, drain. Regards /Fredrik
