I have a problem with using cassandra. Our application does a lot of overwrites and deletes. If I understand correctly cassandra does not actually delete these objects until gc_grace seconds have passed. I tried to "force" gc by setting gc_grace to 0 on an existing column family and running major compaction afterwards. However I did not get disk space back, although I'm pretty much sure that my column family should occupy many times fewer space. We have also a PostgreSQL db and we duplicate each operation with data in both dbs. And the PosgreSQL table is much more smaller than the corresponding cassandra's column family. Does anyone have any suggestions on how can I analyze my problem? Or maybe I'm doing something wrong and there is another way to force gc on an existing column family.
Thanks in advance,