问题
I have table with LCS in Cassandra cluster. I am observing too may tombstones in my cluster so I have decided to reduce GC grace seconds and performing major compaction. Ran nodetoolcompact keyspace table but compaction job ran within a second. it seems major compaction not worked. Can you please help me to understand.
回答1:
If you're actually using the antique Cassandra 2.0, as the label on your question said, then indeed it didn't support major compaction on LCS, and "nodetool compact" only triggered a minor compaction which would have happened anyway (unless explicitly disabled). This was fixed in Cassandra 2.2 - see the issue https://issues.apache.org/jira/browse/CASSANDRA-7272.
There are still ongoing plans to improve major compaction on LCS further - see https://issues.apache.org/jira/browse/CASSANDRA-11817 - but it should already work reasonably well and shouldn't finish "within a second" as you reported - unless you really are running Cassandra 2.0.
来源：https://stackoverflow.com/questions/56422062/major-compaction-on-lcs