[CASSANDRA-7801] A successful INSERT with CAS does not always store data in the DB after a DELETE

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.1.3
• Component/s: Feature/Lightweight Transactions
• Labels: LWT

Environment

PC with Windows 7 and on Linux installation.
Have seen the fault on Cassandra 2.0.9 and Cassandra 2.1.0-rc5

• Assignee: Sylvain Lebresne
• Reporter: Martin Fransson

Authors

Sylvain Lebresne

Reviewers

Aleksey Yeschenko

• Tester: Philip Thompson
• Created: 20/Aug/14 07:01
• Updated: 25/Oct/19 13:10
• Resolved: 06/Nov/14 15:41

Description

When I run a loop with CQL statements to DELETE, INSERT with CAS and then a GET.
The INSERT opertion is successful (Applied), but no data is stored in the database. I have checked the database manually after the test to verify that the DB is empty.

        for (int i = 0; i < 10000; ++i)
        {
            try
            {
                t.del();
                t.cas();
                t.select();
            }
            catch (Exception e)
            {
                System.err.println("i=" + i);
                e.printStackTrace();
                break;
            }
        }


        myCluster = Cluster.builder().addContactPoint("localhost").withPort(12742).build();
        mySession = myCluster.connect();

        mySession.execute("CREATE KEYSPACE IF NOT EXISTS castest WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };");
        mySession.execute("CREATE TABLE IF NOT EXISTS castest.users (userid text PRIMARY KEY, name text)");

        myInsert = mySession.prepare("INSERT INTO castest.users (userid, name) values ('user1', 'calle') IF NOT EXISTS");
        myDelete = mySession.prepare("DELETE FROM castest.users where userid='user1'");
        myGet = mySession.prepare("SELECT * FROM castest.users where userid='user1'");
    }

I can reproduce the fault with the attached program on a PC with windows 7.
You need a cassandra runing and you need to set the port in the program.

Issue Links

• relates to: CASSANDRA-9649 Paxos ballot in StorageProxy could clash