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https://issues.apache.org/jira/browse/CASSANDRA-18934?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17784278#comment-17784278
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Maxwell Guo edited comment on CASSANDRA-18934 at 11/9/23 4:53 AM:
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Thanks [~jjordan] for you reply.
Do we have some flag to show ,we are going to do downgrade ? It is ok to clean
commitlog , or just delete the data in commitlog of unused column for low
version as we are going to do downgrade. But what if we are not going to do
downgrade and just doing drain ? as I know the operation of drain do not tell
the users that cassandra is going to clean commitlog or system table data.
But if we have a nodetool that just called downgrade-drain, it make sense.
was (Author: maxwellguo):
Thanks [~jjordan], do we have some flag to show ,we are going to do downgrade ?
It is ok to clean commitlog , or just delete the data in commitlog of unused
column for low version as we are going to do downgrade. But what if we are not
going to do downgrade and just doing drain ? as I know the operation of drain
do not tell the users that cassandra is going to clean commitlog or system
table data.
But if we have a nodetool that just called downgrade-drain, it make sense.
> Downgrade to 4.1 fails due to schema changes
> --------------------------------------------
>
> Key: CASSANDRA-18934
> URL: https://issues.apache.org/jira/browse/CASSANDRA-18934
> Project: Cassandra
> Issue Type: Bug
> Components: Local/Startup and Shutdown
> Reporter: David Capwell
> Assignee: Maxwell Guo
> Priority: Normal
> Fix For: 5.0-beta, 5.0.x, 5.x
>
>
> We are required to support 5.0 downgrading to 4.1 as a migration step, but we
> don’t have tests to show this is working… I wrote a quick test to make sure a
> change we needed in Accord wouldn’t block the downgrade and see that we fail
> right now.
> {code}
> ERROR 20:56:39 Exiting due to error while processing commit log during
> initialization.
> org.apache.cassandra.db.commitlog.CommitLogReadHandler$CommitLogReadException:
> Unexpected error deserializing mutation; saved to
> /var/folders/h1/s_3p1x3s3hl0hltbpck67m0h0000gn/T/mutation4184214444767150092dat.
> This may be caused by replaying a mutation against a table with the same
> name but incompatible schema. Exception follows: java.lang.RuntimeException:
> Unknown column compaction_properties during deserialization
> at
> org.apache.cassandra.db.commitlog.CommitLogReader.readMutation(CommitLogReader.java:464)
> at
> org.apache.cassandra.db.commitlog.CommitLogReader.readSection(CommitLogReader.java:397)
> at
> org.apache.cassandra.db.commitlog.CommitLogReader.readCommitLogSegment(CommitLogReader.java:244)
> at
> org.apache.cassandra.db.commitlog.CommitLogReader.readCommitLogSegment(CommitLogReader.java:147)
> at
> org.apache.cassandra.db.commitlog.CommitLogReplayer.replayFiles(CommitLogReplayer.java:191)
> at
> org.apache.cassandra.db.commitlog.CommitLog.recoverFiles(CommitLog.java:223)
> at
> org.apache.cassandra.db.commitlog.CommitLog.recoverSegmentsOnDisk(CommitLog.java:204)
> {code}
> This was caused by a schema change in CASSANDRA-18061
> {code}
> /*
> * 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.io.IOException;
> import java.io.File;
> import java.util.concurrent.atomic.AtomicBoolean;
> import org.junit.Test;
> import org.apache.cassandra.distributed.api.IUpgradeableInstance;
> public class DowngradeTest extends UpgradeTestBase
> {
> @Test
> public void test() throws Throwable
> {
> AtomicBoolean first = new AtomicBoolean(true);
> new TestCase()
> .nodes(1)
> .withConfig(c -> {
> if (first.compareAndSet(true, false))
> c.set("storage_compatibility_mode", "CASSANDRA_4");
> })
> .downgradeTo(v41)
> .setup(cluster -> {})
> // Uncomment if you want to test what happens after reading the commit log,
> which fails right now
> // .runBeforeNodeRestart((cluster, nodeId) -> {
> // IUpgradeableInstance inst = cluster.get(nodeId);
> // File f = new File((String)
> inst.config().get("commitlog_directory"));
> // deleteRecursive(f);
> // })
> .runAfterClusterUpgrade(cluster -> {})
> .run();
> }
> private void deleteRecursive(File f)
> {
> if (f.isDirectory())
> {
> File[] children = f.listFiles();
> if (children != null)
> {
> for (File c : children)
> deleteRecursive(c);
> }
> }
> f.delete();
> }
> }
> {code}
> {code}
> diff --git
> a/test/distributed/org/apache/cassandra/distributed/upgrade/UpgradeTestBase.java
>
> b/test/distributed/org/apache/cassandra/distributed/upgrade/UpgradeTestBase.java
> index 5ee8780204..b4111e3b44 100644
> ---
> a/test/distributed/org/apache/cassandra/distributed/upgrade/UpgradeTestBase.java
> +++
> b/test/distributed/org/apache/cassandra/distributed/upgrade/UpgradeTestBase.java
> @@ -226,6 +226,12 @@ public class UpgradeTestBase extends DistributedTestBase
> return this;
> }
> + public TestCase downgradeTo(Semver to)
> + {
> + upgrade.add(new TestVersions(versions.getLatest(CURRENT),
> Collections.singletonList(versions.getLatest(to))));
> + return this;
> + }
> +
> /**
> * performs all supported upgrade paths that exist in between from
> and to that include the current version.
> * This call is equivalent to calling {@code upgradesTo(from,
> CURRENT).upgradesFrom(CURRENT, to)}.
> {code}
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