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https://issues.apache.org/jira/browse/FLINK-4067?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15362172#comment-15362172
]
ASF GitHub Bot commented on FLINK-4067:
---------------------------------------
Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/2194#discussion_r69520756
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/savepoint/SavepointV0Serializer.java
---
@@ -0,0 +1,58 @@
+/*
+ * 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.flink.runtime.checkpoint.savepoint;
+
+import org.apache.flink.runtime.checkpoint.CompletedCheckpoint;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectInputStream;
+import java.io.OutputStream;
+
+/**
+ * Serializer for {@link SavepointV0} instances.
+ *
+ * <p>This format was introduced with Flink 1.0.0 and simply wraps a
+ * {@link CompletedCheckpoint} instance and uses plain Java serialization.
+ * That's why we have to stick to the exact same format, including classes,
+ * which are only part of our code base for backwards compatability.
+ */
+public class SavepointV0Serializer implements
SavepointSerializer<SavepointV0> {
+
+ public static final SavepointV0Serializer INSTANCE = new
SavepointV0Serializer();
--- End diff --
Maybe we should add a private constructor so that nobody can instantiate
this class.
> Add version header to savepoints
> --------------------------------
>
> Key: FLINK-4067
> URL: https://issues.apache.org/jira/browse/FLINK-4067
> Project: Flink
> Issue Type: Improvement
> Affects Versions: 1.0.3
> Reporter: Ufuk Celebi
> Assignee: Ufuk Celebi
> Fix For: 1.1.0
>
>
> Adding a header with version information to savepoints ensures that we can
> migrate savepoints between Flink versions in the future (for example when
> changing internal serialization formats between versions).
> After talking with Till, we propose to add the following meta data:
> - Magic number (int): identify data as savepoint
> - Version (int): savepoint version (independent of Flink version)
> - Data Offset (int): specifies at which point the actual savepoint data
> starts. With this, we can allow future Flink versions to add fields to the
> header without breaking stuff, e.g. Flink 1.1 could read savepoints of Flink
> 2.0.
> For Flink 1.0 savepoint support, we have to try reading the savepoints
> without a header before failing if we don't find the magic number.
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