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From crypto five <>
Subject Cassandra dying when gets many deletes
Date Tue, 24 Apr 2012 01:50:07 GMT

I have 50 millions of rows in column family on 4G RAM box. I allocatedf 2GB
to cassandra.
I have program which is traversing this CF and cleaning some data there, it
generates about 20k delete statements per second.
After about of 3 millions deletions cassandra stops responding to queries:
it doesn't react to CLI, nodetool etc.
I see in the logs that it tries to free some memory but can't even if I
wait whole day.
Also I see following in  the logs:

INFO [ScheduledTasks:1] 2012-04-23 18:38:13,333 (line
2647) Unable to reduce heap usage since there are no dirty column families

When I am looking at memory dump I see that memory goes to
ConcurrentSkipListMap(10%), HeapByteBuffer(13%), DecoratedKey(6%),
int[](6%), BigInteger(8.2%), ConcurrentSkipListMap$HeadIndex(7.2%),
ColumnFamily(6.5%), ThreadSafeSortedColumns(13.7%), long[](5.9%).

What can I do to make cassandra stop dying?
Why it can't free the memory?
Any ideas?

Thank you.

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