aokolnychyi commented on code in PR #10176: URL: https://github.com/apache/iceberg/pull/10176#discussion_r1697760344
########## data/src/main/java/org/apache/iceberg/data/GeneratePartitionStats.java: ########## @@ -0,0 +1,122 @@ +/* + * 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.data; + +import java.io.IOException; +import java.io.UncheckedIOException; +import java.util.List; +import java.util.Map; +import java.util.concurrent.ConcurrentSkipListMap; +import org.apache.iceberg.ImmutableGenericPartitionStatisticsFile; +import org.apache.iceberg.ManifestFile; +import org.apache.iceberg.PartitionStatisticsFile; +import org.apache.iceberg.PartitionStatsUtil; +import org.apache.iceberg.Partitioning; +import org.apache.iceberg.Schema; +import org.apache.iceberg.Snapshot; +import org.apache.iceberg.Table; +import org.apache.iceberg.io.CloseableIterable; +import org.apache.iceberg.io.OutputFile; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.iceberg.types.Comparators; +import org.apache.iceberg.types.Types; +import org.apache.iceberg.util.SnapshotUtil; +import org.apache.iceberg.util.Tasks; +import org.apache.iceberg.util.ThreadPools; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +public class GeneratePartitionStats { + private static final Logger LOG = LoggerFactory.getLogger(GeneratePartitionStats.class); + + private final Table table; + private String branch; + + public GeneratePartitionStats(Table table) { + this.table = table; + } + + public GeneratePartitionStats(Table table, String branch) { + this.table = table; + this.branch = branch; + } + + /** + * Computes the partition stats for the current snapshot and writes it into the metadata folder. + * + * @return {@link PartitionStatisticsFile} for the latest snapshot id or null if table doesn't + * have any snapshot. + */ + public PartitionStatisticsFile generate() { + Snapshot currentSnapshot = SnapshotUtil.latestSnapshot(table, branch); + if (currentSnapshot == null) { + Preconditions.checkArgument( + branch == null, "Couldn't find the snapshot for the branch %s", branch); + return null; + } + + Types.StructType partitionType = Partitioning.partitionType(table); + // Map of partitionData, partition-stats-entry per partitionData. + // Sorting the records based on partition as per spec. + Map<Record, Record> partitionEntryMap = + new ConcurrentSkipListMap<>(Comparators.forType(partitionType)); Review Comment: I am worried about the overhead of maintaining the map sorted on writes (there will be a lot of writes). I wonder whether using `ConcurrentHashMap` and sorting once at the end will be more efficient. Can we add a JMH benchmark to verify this? If we notice thread-safe collections cause significant overhead, we can switch to aggregating manifests concurrently and doing one more pass for the final aggregation. Then we will be able to avoid concurrency problems without overhead. We will only be able to tell if thread-safe collections cause significant overhead after having a good benchmark. -- 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
