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Sylvain Lebresne commented on CASSANDRA-5925: --------------------------------------------- Don't you have more stack trace in the log? To have a NPE in the MutationStage is definitively a bug, but it would be immensely easier to find what's the problem with a stack trace. And there should be a trace. > Race condition in update lightweight transaction > ------------------------------------------------ > > Key: CASSANDRA-5925 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5925 > Project: Cassandra > Issue Type: Bug > Environment: 3 node Cassandra 2.0.0-rc2 cluster. Java driver 1.0.2. > Reporter: Phil Persad > > I'm building some tests for a Cassandra PoC. One scenario I need to test is > consumption of 1 time tokens. These tokens must be consumed exactly once. > The cluster involved is a 3 node cluster. All queries are run with > ConsistencyLevel.QUORUM. I'm using the following queries: > CREATE KEYSPACE IF NOT EXISTS test WITH replication = { 'class' : > 'SimpleStrategy', 'replication_factor' : 3 }; > CREATE TABLE IF NOT EXISTS tkns (tkn blob, consumed boolean, PRIMARY KEY > (tkn)); > INSERT INTO tkns (tkn, consumed) VALUES (?,FALSE) USING TTL 30; > UPDATE tkns USING TTL 1 SET consumed = TRUE WHERE tkn = ? IF consumed = FALSE; > I use the '[applied]' column in the result set of the update statement to > determine whether the token has been successfully consumed or if the token is > being replayed. > My test involves concurrently executing many sets of 1 insert and 2 update > statements (using Session#execute on BoundStatemnts) then checking to make > sure that only one of the updates was applied. > When I run this test with relatively few iterations (~100) my results are > what I expect (exactly 1 update succeeds). At ~1000 iterations, I start > seeing both updates reporting success in 1-2% of cases. While my test is > running, I see corresponding error entries in the Cassandra log: > ERROR 15:34:53,583 Exception in thread Thread[MutationStage:522,5,main] > java.lang.NullPointerException > ERROR 15:34:53,584 Exception in thread Thread[MutationStage:474,5,main] > java.lang.NullPointerException > ERROR 15:34:53,584 Exception in thread Thread[MutationStage:536,5,main] > java.lang.NullPointerException > ERROR 15:34:53,729 Exception in thread Thread[MutationStage:480,5,main] > java.lang.NullPointerException > ERROR 15:34:53,729 Exception in thread Thread[MutationStage:534,5,main] > java.lang.NullPointerException > Thanks. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira