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Robert Wille commented on CASSANDRA-9194: ----------------------------------------- I actually haven't run it to OOM either, although I assume it would. The JVM becomes impossibly slow with 30 second GC's. Actually, I dug around some more in my email and I found a conversation I had with [~benedict] who fixed this problem back in 2.0.6. My email confirmed that https://issues.apache.org/jira/browse/CASSANDRA-6655 is the ticket that contained the patch that fixed my woes a year ago. Now I'm more confused than ever why this bug still happens. > Delete-only workloads crash Cassandra > ------------------------------------- > > Key: CASSANDRA-9194 > URL: https://issues.apache.org/jira/browse/CASSANDRA-9194 > Project: Cassandra > Issue Type: Bug > Environment: 2.0.14 > Reporter: Robert Wille > Assignee: Benedict > Fix For: 2.0.15 > > > The size of a tombstone is not properly accounted for in the memtable. A > memtable which has only tombstones will never get flushed. It will grow until > the JVM runs out of memory. The following program easily demonstrates the > problem. > {code} > Cluster.Builder builder = Cluster.builder(); > > Cluster c = > builder.addContactPoints("cas121.devf3.com").build(); > > Session s = c.connect(); > > s.execute("CREATE KEYSPACE IF NOT EXISTS test WITH replication > = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 }"); > s.execute("CREATE TABLE IF NOT EXISTS test.test(id INT PRIMARY > KEY)"); > PreparedStatement stmt = s.prepare("DELETE FROM test.test WHERE > id = :id"); > int id = 0; > > while (true) > { > s.execute(stmt.bind(id)); > > id++; > }{code} > This program should run forever, but eventually Cassandra runs out of heap > and craps out. You needn't wait for Cassandra to crash. If you run "nodetool > cfstats test.test" while it is running, you'll see Memtable cell count grow, > but Memtable data size will remain 0. > This issue was fixed once before. I received a patch for version 2.0.5 (I > believe), which contained the fix, but the fix has apparently been lost, > because it is clearly broken, and I don't see the fix in the change logs. -- This message was sent by Atlassian JIRA (v6.3.4#6332)