ifesdjeen commented on code in PR #4015: URL: https://github.com/apache/cassandra/pull/4015#discussion_r2018030373
########## test/distributed/org/apache/cassandra/distributed/upgrade/MixedModePaxosTest.java: ########## @@ -0,0 +1,226 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.cassandra.distributed.upgrade; + +import java.nio.ByteBuffer; +import java.util.UUID; +import java.util.concurrent.TimeUnit; + +import org.junit.Assert; +import org.junit.Test; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.cassandra.db.SimpleBuilders; +import org.apache.cassandra.db.marshal.Int32Type; +import org.apache.cassandra.db.partitions.PartitionUpdate; +import org.apache.cassandra.db.rows.Row; +import org.apache.cassandra.dht.Murmur3Partitioner; +import org.apache.cassandra.distributed.api.ConsistencyLevel; +import org.apache.cassandra.distributed.api.Feature; +import org.apache.cassandra.distributed.api.ICoordinator; +import org.apache.cassandra.net.MessagingService; +import org.apache.cassandra.schema.TableId; +import org.apache.cassandra.schema.TableMetadata; +import org.apache.cassandra.service.paxos.Ballot; +import org.apache.cassandra.utils.ByteBufferUtil; + +import static java.lang.String.format; + +public class MixedModePaxosTest extends UpgradeTestBase +{ + private static final Logger logger = LoggerFactory.getLogger(MixedModePaxosTest.class); + + + /** + * Tests the mixed mode loop bug in CASSANDRA-20493 + * + * Paxos uses a 'zero' ballot in place of null when it doesn't find a ballot in system.paxos. CEP-14 changed the lsb + * of the zero ballot uuid from -9187201950435737472 to 0. It also removed the check added in CASSANDRA-12043, since + * the way it read and filtered ttld paxos data had been improved. However, this means that 4.1 and higher paxos + * coordinators, the prepare phase will always interpret the most recent commits from 4.0 and lower nodes as being + * less than its own and will update them with its slightly higher zero ballot and empty partition update. In cases + * where this is the first paxos operation on a key, or the previously ttl'd paxos data on disk had been purged, this + * would just add a retry step as it updated the 4.0 and lower hosts with it's zero ballot. On nodes where there was + * ttl'd paxos data though, the ttl'd data on disk would shadow this update and the conflicting 'zero' value would + * cause the prepare phase to get into an infinite loop. + */ + @Test + public void upgradeAwareTtldPaxosStateTest() throws Throwable + { + String keyspace = KEYSPACE; + String table = "tbl"; + int gcGrace = 10; // 1 day + new TestCase() + .withConfig(c -> c.with(Feature.GOSSIP, Feature.NETWORK)) + .nodes(2) + .nodesToUpgrade(1) + // all upgrades from v30 up, excluding v30->v3X and from v40 + .singleUpgrade(v40) + .setup(cluster -> { + cluster.schemaChange(format("CREATE TABLE %s.%s (k int primary key, v int) " + + "WITH gc_grace_seconds=%s", keyspace, table, gcGrace)); + }) + .runAfterClusterUpgrade(cluster -> { + // disable compaction to prevent paxos state from being purged + cluster.forEach(instance -> instance.nodetool("disableautocompaction")); + + // insert a ttl'd committed paxos state + long ballotMicros = TimeUnit.NANOSECONDS.toMicros(System.currentTimeMillis()); + FakePaxosHelper helper = FakePaxosHelper.create(cluster.coordinator(1), keyspace, table, gcGrace, ballotMicros); + + // confirm none of the nodes have paxos state + for (int i=1; i<=cluster.size(); i++) + Assert.assertEquals(0, cluster.coordinator(i).execute("SELECT * FROM system.paxos", ConsistencyLevel.ONE).length); + + + // save commit to both nodes + helper.saveCommit(cluster.coordinator(1)); + helper.saveCommit(cluster.coordinator(2)); + + // wait for the paxos state to expire + Thread.sleep(TimeUnit.SECONDS.toMillis(gcGrace * 2)); Review Comment: Pardon me: of course it is 10 seconds; glanced at it too quickly. -- This is an automated message from the Apache Git Service. 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