InvalidQueryException intermittently while updating a table in Cassandra

Question

I am facing a peculiar issue. We have set consistency to LOCAL_QUORUM. I have a long running job which updates the DB from time to time. In between these updates we see the below issue intermittently:

com.datastax.driver.core.exceptions.InvalidQueryException: SERIAL is not supported as conditional update commit consistency. Use ANY if you mean "make sure it is accepted but I don't care how many replicas commit it for non-SERIAL reads"
    at com.datastax.driver.core.exceptions.InvalidQueryException.copy(InvalidQueryException.java:35) ~[cassandra-driver-core-2.1.7.1.jar:na]
    at com.datastax.driver.core.DefaultResultSetFuture.extractCauseFromExecutionException(DefaultResultSetFuture.java:269) ~[cassandra-driver-core-2.1.7.1.jar:na]
    at com.datastax.driver.core.DefaultResultSetFuture.getUninterruptibly(DefaultResultSetFuture.java:183) ~[cassandra-driver-core-2.1.7.1.jar:na]
    at com.datastax.driver.core.AbstractSession.execute(AbstractSession.java:52) ~[cassandra-driver-core-2.1.7.1.jar:na]

Not sure why this comes up, as anyways we have not set our consistency to SERIAL. Any help/advice/pointers would be great. Below are the DSE and cql versions:

[cqlsh 5.0.1 | Cassandra 2.1.15.1403 | DSE 4.8.9 | CQL spec 3.2.1 | Native protocol v3]

Answer 1

It looks like that you hit JAVA-764 bug. The DSE 4.8.9 uses Java driver 2.1.7.1, while the bug is fixed in the 2.1.10, so you'll need to upgrade your code to use updated version of driver.