RussellSpitzer commented on code in PR #12306: URL: https://github.com/apache/iceberg/pull/12306#discussion_r1963944890
########## core/src/main/java/org/apache/iceberg/actions/RewriteGroupBase.java: ########## @@ -0,0 +1,104 @@ +/* + * 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.iceberg.actions; + +import java.util.List; +import org.apache.iceberg.ContentFile; +import org.apache.iceberg.ContentScanTask; + +/** + * Container class representing a set of files to be rewritten by a {@link FileRewriteRunner}. + * + * @param <I> the Java type of the plan info member like {@link RewriteDataFiles.FileGroupInfo} or + * {@link RewritePositionDeleteFiles.FileGroupInfo} + * @param <T> the Java type of the input scan tasks (input) + * @param <F> the Java type of the content files (input and output) + */ +public abstract class RewriteGroupBase<I, T extends ContentScanTask<F>, F extends ContentFile<F>> { + private final I info; + private final List<T> fileScanTasks; + private final long maxOutputFileSize; + private final long inputSplitSize; + private final int expectedOutputFiles; + + RewriteGroupBase( + I info, + List<T> fileScanTasks, + long maxOutputFileSize, + long inputSplitSize, + int expectedOutputFiles) { + this.info = info; + this.fileScanTasks = fileScanTasks; + this.maxOutputFileSize = maxOutputFileSize; + this.inputSplitSize = inputSplitSize; + this.expectedOutputFiles = expectedOutputFiles; + } + + /** Identifiers and partition information about the group. */ + public I info() { + return info; + } + + /** Scan tasks for input files. */ + public List<T> fileScanTasks() { + return fileScanTasks; + } + + /** Accumulated size for the input files. */ + public long inputFilesSizeInBytes() { + return fileScanTasks.stream().mapToLong(T::length).sum(); + } + + /** Number of the input files. */ + public int inputFileNum() { + return fileScanTasks.size(); + } + + /** + * While we create tasks that should all be smaller than our target size, there is a chance that + * the actual data will end up being larger than our target size due to various factors of + * compression, serialization, which are outside our control. If this occurs, instead of making a + * single file that is close in size to our target, we would end up producing one file of the + * target size, and then a small extra file with the remaining data. + * + * <p>For example, if our target is 512 MB, we may generate a rewrite task that should be 500 MB. + * When we write the data we may find we actually have to write out 530 MB. If we use the target + * size while writing, we would produce a 512 MB file and an 18 MB file. If instead we use a + * larger size estimated by this method, then we end up writing a single file. + * + * @return the target size plus one half of the distance between max and target + */ + public long maxOutputFileSize() { + return maxOutputFileSize; + } + + /** + * Determines the reader split size as the input size divided by the desired number of output Review Comment: Also specific to the planner. I'm also not sure if split size is a good name here. -- 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. To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
