nsivabalan commented on a change in pull request #1858: URL: https://github.com/apache/hudi/pull/1858#discussion_r467603220
########## File path: hudi-client/src/main/java/org/apache/hudi/table/upgrade/UpgradeDowngrade.java ########## @@ -0,0 +1,153 @@ +/* + * 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.hudi.table.upgrade; + +import org.apache.hudi.common.table.HoodieTableConfig; +import org.apache.hudi.common.table.HoodieTableMetaClient; +import org.apache.hudi.common.table.HoodieTableVersion; +import org.apache.hudi.common.util.FileIOUtils; +import org.apache.hudi.config.HoodieWriteConfig; + +import org.apache.hadoop.fs.FSDataOutputStream; +import org.apache.hadoop.fs.FileSystem; +import org.apache.hadoop.fs.Path; +import org.apache.log4j.LogManager; +import org.apache.log4j.Logger; +import org.apache.spark.api.java.JavaSparkContext; + +import java.io.IOException; +import java.util.Date; +import java.util.Properties; + +/** + * Helper class to assist in upgrading/downgrading Hoodie when there is a version change. + */ +public class UpgradeDowngrade { + + private static final Logger LOG = LogManager.getLogger(UpgradeDowngrade.class); + public static final String HOODIE_UPDATED_PROPERTY_FILE = "hoodie.properties.updated"; + + private HoodieTableMetaClient metaClient; + private HoodieWriteConfig config; + private JavaSparkContext jsc; + private transient FileSystem fs; + private Path updatedPropsFilePath; + private Path propsFilePath; + + /** + * Perform Upgrade or Downgrade steps if required and updated table version if need be. + * <p> + * Starting from version 0.6.0, this upgrade/downgrade step will be added in all write paths. + * + * Essentially, if a dataset was created using any pre 0.6.0(for eg 0.5.3), and Hoodie version was upgraded to 0.6.0, + * Hoodie table version gets bumped to 1 and there are some upgrade steps need to be executed before doing any writes. + * Similarly, if a dataset was created using Hoodie version 0.6.0 or Hoodie table version 1 and then hoodie was downgraded + * to pre 0.6.0 or to Hoodie table version 0, then some downgrade steps need to be executed before proceeding w/ any writes. + * + * On a high level, these are the steps performed + * + * Step1 : Understand current hoodie table version and table version from hoodie.properties file + * Step2 : Delete any left over .upgraded from previous upgrade/downgrade Review comment: updated/upgraded(file is named as HOODIE_UPDATED_PROPERTY_FILE). Lets use same terminology everywhere. Ignore addressing renaming/java docs/refactoring comments for now. Let's get the patch in for now. But leaving comments so that I can take it up after 0.6.0 release. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
