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From "Oliver Lockwood (JIRA)" <>
Subject [jira] [Created] (CASSANDRA-11288) Schema agreement appears to be false positive following a DROP TABLE command
Date Tue, 01 Mar 2016 17:37:18 GMT
Oliver Lockwood created CASSANDRA-11288:

             Summary: Schema agreement appears to be false positive following a DROP TABLE
                 Key: CASSANDRA-11288
             Project: Cassandra
          Issue Type: Bug
         Environment: Cassandra (DSE 4.6.7)
2 nodes
Connecting with Datastax Java driver 2.1.8
            Reporter: Oliver Lockwood
            Priority: Minor

As part of a schema migration operation, our application is calling the following operations
on the Java driver consecutively:
{{session.execute("DROP TABLE table_name");
session.execute("CREATE TABLE table_name (...)");}}

The second of these sometimes fails with a {{DriverException}} whose message is "Table keyspace.table_name
already exists".

In the schema migration operation, there's 4 of these drop/create pairings and, although it's
random which exact one fails, we've never managed to get further than the third operation
in approximately 10 attempts - so there's a reasonably high proportion of failure.

I don't believe this is a driver issue because the driver is checking for schema agreement
(as per
and we are seeing a log message to that effect.
{{c.d.d.c.ControlConnection - [] [] [] [] [] [] [] [] Checking for schema agreement: versions
are [02bce936-fddd-3bef-bb54-124d31bede57]}}.
(This log message appears in between our own logs which say "Executing statement DROP TABLE..."
and "Executing statement CREATE TABLE...", so we can be reasonably sure this log message refers
to the DROP operation being viewed as "in agreement".

Could this be a bug in the Cassandra server erroneously reporting that the schemas are in
agreement across the 2 nodes when, in fact, they are not?

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