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From Ross Black <ross.w.bl...@gmail.com>
Subject tombstones problem with 1.0.8
Date Thu, 22 Mar 2012 01:38:00 GMT
Hi,

We recently moved from 0.8.2 to 1.0.8 and the behaviour seems to have
changed so that tombstones are now not being deleted.

Our application continually adds and removes columns from Cassandra.  We
have set a short gc_grace time (3600) since our application would
automatically delete zombies if they appear.
Under 0.8.2, the tombstones remained at a relatively constant number.
Under 1.0.8, the tombstones have been continually increasing so that they
exceed the size of our real data (at this stage we have over 100G of
tombstones).
Even after running a full compact the new compacted SSTable contains a
massive number of tombstones, many that are several weeks old.

Have I missed some new configuration option to allow deletion of tombstones?

I also noticed that one of the changes between 0.8.2 and 1.0.8 was
https://issues.apache.org/jira/browse/CASSANDRA-2786 which changed code to
"avoid dropping tombstones when they might still be needed to shadow data
in another sstable".
Could this be having an impact since we continually add and remove columns
even while a major compact is executing?


Thanks,
Ross

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