[CASSANDRA-6837] Batch CAS does not support LOCAL_SERIAL

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.0.7
• Component/s: Feature/Lightweight Transactions
• Labels: LWT
• Severity: Normal
• Assignee: Sylvain Lebresne
• Reporter: Nicolas Favre-Felix

Authors

Sylvain Lebresne

Reviewers

Jonathan Ellis

• Created: 11/Mar/14 16:04
• Updated: 25/Oct/19 13:10
• Resolved: 17/Mar/14 10:17

Description

The batch CAS feature introduced in Cassandra 2.0.6 does not support the LOCAL_SERIAL consistency level, and always uses SERIAL.

Create a cluster with 4 nodes with the following topology:

Datacenter: DC2
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address    Load       Tokens  Owns   Host ID                               Rack
UN  127.0.0.3  269 KB     256     26.3%  ae92d997-6042-42d9-b447-943080569742  RAC1
UN  127.0.0.4  197.81 KB  256     25.1%  3edc92d7-9d1b-472a-8452-24dddbc4502c  RAC1
Datacenter: DC1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address    Load       Tokens  Owns   Host ID                               Rack
UN  127.0.0.1  226.92 KB  256     24.8%  dbc17bd7-1ede-47a2-9b31-6063752d6eb3  RAC1
UN  127.0.0.2  179.27 KB  256     23.7%  bb0ad285-34d2-4989-a664-b068986ab6fa  RAC1

In cqlsh:

cqlsh> CREATE KEYSPACE foo WITH replication = {'class': 'NetworkTopologyStrategy', 'DC1': 2, 'DC2': 2};
cqlsh> USE foo;
cqlsh:foo> CREATE TABLE bar (x text, y bigint, z bigint, t bigint, PRIMARY KEY(x,y));

Kill nodes 127.0.0.3 and 127.0.0.4:

Datacenter: DC2
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address    Load       Tokens  Owns   Host ID                               Rack
DN  127.0.0.3  262.37 KB  256     26.3%  ae92d997-6042-42d9-b447-943080569742  RAC1
DN  127.0.0.4  208.04 KB  256     25.1%  3edc92d7-9d1b-472a-8452-24dddbc4502c  RAC1
Datacenter: DC1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address    Load       Tokens  Owns   Host ID                               Rack
UN  127.0.0.1  214.82 KB  256     24.8%  dbc17bd7-1ede-47a2-9b31-6063752d6eb3  RAC1
UN  127.0.0.2  178.23 KB  256     23.7%  bb0ad285-34d2-4989-a664-b068986ab6fa  RAC1

Connect to 127.0.0.1 in DC1 and run a CAS batch at CL.LOCAL_SERIAL+LOCAL_QUORUM:

        final Cluster cluster = new Cluster.Builder()
                .addContactPoint("127.0.0.1")
                .withLoadBalancingPolicy(new DCAwareRoundRobinPolicy("DC1"))
                .build();

        final Session session = cluster.connect("foo");

        Batch batch = QueryBuilder.batch();
        batch.add(new SimpleStatement("INSERT INTO bar (x,y,z) VALUES ('abc', 123, 1) IF NOT EXISTS"));
        batch.add(new SimpleStatement("UPDATE bar SET t=2 WHERE x='abc' AND y=123"));

        batch.setConsistencyLevel(ConsistencyLevel.LOCAL_QUORUM);
        batch.setSerialConsistencyLevel(ConsistencyLevel.LOCAL_SERIAL);

        session.execute(batch);

The batch fails with:

Caused by: com.datastax.driver.core.exceptions.UnavailableException: Not enough replica available for query at consistency SERIAL (3 required but only 2 alive)
	at com.datastax.driver.core.Responses$Error$1.decode(Responses.java:44)
	at com.datastax.driver.core.Responses$Error$1.decode(Responses.java:33)
	at com.datastax.driver.core.Message$ProtocolDecoder.decode(Message.java:182)
	at org.jboss.netty.handler.codec.oneone.OneToOneDecoder.handleUpstream(OneToOneDecoder.java:66)
	... 21 more