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https://issues.apache.org/jira/browse/GIRAPH-1188?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16444803#comment-16444803
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ASF GitHub Bot commented on GIRAPH-1188:
----------------------------------------
Github user yukselakinci commented on a diff in the pull request:
https://github.com/apache/giraph/pull/70#discussion_r182885824
--- Diff:
giraph-core/src/main/java/org/apache/giraph/writable/kryo/GiraphClassResolver.java
---
@@ -0,0 +1,308 @@
+/*
+ * 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.giraph.writable.kryo;
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.KryoException;
+import com.esotericsoftware.kryo.Registration;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+import com.esotericsoftware.kryo.util.DefaultClassResolver;
+import com.esotericsoftware.kryo.util.ObjectMap;
+import org.apache.giraph.zk.ZooKeeperExt;
+import org.apache.zookeeper.CreateMode;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.ZooDefs;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.List;
+
+import static com.esotericsoftware.kryo.util.Util.getWrapperClass;
+
+/**
+ * This class resolver assigns unique classIds for every class that was not
+ * explicitly registered. It uses zookeeper for consistent mapping across
all
+ * nodes.
+ */
+public class GiraphClassResolver extends DefaultClassResolver {
+ /** Length of the ZK sequence number */
+ private static final int SEQUENCE_NUMBER_LENGTH = 10;
+ /** Base ID to start for class name assignments.
+ * This number has to be high enough to not conflict with
+ * explicity registered class IDs.
+ * */
+ private static final int BASE_CLASS_ID = 10000;
+
+ /** Class name to ID cache */
+ private static Map<String, Integer> CLASS_NAME_TO_ID = new HashMap();
+ /** ID to class name cache */
+ private static Map<Integer, String> ID_TO_CLASS_NAME = new HashMap();
+ /** Zookeeper */
+ private static ZooKeeperExt ZK;
--- End diff --
Without static, we have to pass this information as a parameter. But there
are so many places where the kryo objects are created, so it would not be
pretty to delegate this information from BspService to all these places.
> Add kryo custom class resolver for faster serialization.
> --------------------------------------------------------
>
> Key: GIRAPH-1188
> URL: https://issues.apache.org/jira/browse/GIRAPH-1188
> Project: Giraph
> Issue Type: Improvement
> Reporter: Yuksel Akinci
> Priority: Major
>
> The custom class resolver allows kryo to always use the integer IDs for
> classes that are agreed by all nodes running the job. Default class resolver
> always writes the full class name of the first encountered class type to the
> stream, and then it assigns an integer for subsequent instances. These
> changes make the serialization faster by eliminating the need to write the
> full name for the first encountered class instance.
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