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From "Nick Bailey (JIRA)" <>
Subject [jira] [Created] (CASSANDRA-4396) Subcolumns not removed when compacting tombstoned super column
Date Fri, 29 Jun 2012 17:36:44 GMT
Nick Bailey created CASSANDRA-4396:

             Summary: Subcolumns not removed when compacting tombstoned super column
                 Key: CASSANDRA-4396
             Project: Cassandra
          Issue Type: Bug
            Reporter: Nick Bailey

When we compact a tombstone for a super column with the old data for that super column, we
end up writing the deleted super column and all the subcolumn data that is now worthless to
the new sstable. This is especially inefficient when reads need to scan tombstones during
a slice.

Here is the output of a simple test I ran to confirm:

insert supercolumn, then flush
Nicks-MacBook-Pro:12:20:52 cassandra-1.0] cassandra$ bin/sstable2json ~/.ccm/1node/node1/data/Keyspace2/Super4-hd-1-Data.db

"6b657931": {"supercol1": {"deletedAt": -9223372036854775808, "subColumns": [["737562636f6c31","7468697320697320612074657374",1340990212532000]]}}

delete supercolumn, flush again

[Nicks-MacBook-Pro:12:20:59 cassandra-1.0] cassandra$ bin/nodetool -h localhost flush
[Nicks-MacBook-Pro:12:22:41 cassandra-1.0] cassandra$ bin/sstable2json ~/.ccm/1node/node1/data/Keyspace2/Super4-hd-2-Data.db

"6b657931": {"supercol1": {"deletedAt": 1340990544005000, "subColumns": []}}

compact and check resulting sstable

[Nicks-MacBook-Pro:12:22:55 cassandra-1.0] cassandra$ bin/nodetool -h localhost compact 
[Nicks-MacBook-Pro:12:23:09 cassandra-1.0] cassandra$ bin/sstable2json ~/.ccm/1node/node1/data/Keyspace2/Super4-hd-3-Data.db

"6b657931": {"supercol1": {"deletedAt": 1340990544005000, "subColumns": [["737562636f6c31","7468697320697320612074657374",1340990212532000]]}}
[Nicks-MacBook-Pro:12:23:20 cassandra-1.0] cassandra$ 

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