szehon-ho commented on code in PR #10288: URL: https://github.com/apache/iceberg/pull/10288#discussion_r1638468180
########## spark/v3.5/spark/src/main/java/org/apache/iceberg/spark/actions/NDVSketchGenerator.java: ########## @@ -0,0 +1,176 @@ +/* + * 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.spark.actions; + +import java.io.IOException; +import java.nio.ByteBuffer; +import java.util.Iterator; +import java.util.List; +import java.util.Map; +import java.util.UUID; +import java.util.stream.Collectors; +import org.apache.datasketches.theta.CompactSketch; +import org.apache.datasketches.theta.SetOperationBuilder; +import org.apache.datasketches.theta.UpdateSketch; +import org.apache.iceberg.GenericBlobMetadata; +import org.apache.iceberg.GenericStatisticsFile; +import org.apache.iceberg.HasTableOperations; +import org.apache.iceberg.StatisticsFile; +import org.apache.iceberg.Table; +import org.apache.iceberg.TableOperations; +import org.apache.iceberg.io.FileIO; +import org.apache.iceberg.io.OutputFile; +import org.apache.iceberg.puffin.Blob; +import org.apache.iceberg.puffin.Puffin; +import org.apache.iceberg.puffin.PuffinWriter; +import org.apache.iceberg.puffin.StandardBlobTypes; +import org.apache.iceberg.relocated.com.google.common.collect.ImmutableList; +import org.apache.iceberg.relocated.com.google.common.collect.ImmutableMap; +import org.apache.iceberg.relocated.com.google.common.collect.Lists; +import org.apache.iceberg.relocated.com.google.common.collect.Maps; +import org.apache.iceberg.types.Types; +import org.apache.spark.api.java.JavaPairRDD; +import org.apache.spark.api.java.function.Function2; +import org.apache.spark.sql.Column; +import org.apache.spark.sql.Dataset; +import org.apache.spark.sql.Row; +import org.apache.spark.sql.SparkSession; +import org.apache.spark.sql.functions; +import org.apache.spark.sql.internal.SQLConf; +import scala.Tuple2; + +public class NDVSketchGenerator { + + private NDVSketchGenerator() {} + + static StatisticsFile generateNDV( + SparkSession spark, Table table, long snapshotId, String... columnsToBeAnalyzed) + throws IOException { + List<String> columnList; + if (columnsToBeAnalyzed == null || columnsToBeAnalyzed.length == 0) { + columnList = + table.schema().columns().stream() + .map(Types.NestedField::name) + .collect(Collectors.toList()); + } else { + columnList = Lists.newArrayList(columnsToBeAnalyzed); + } + Iterator<Tuple2<String, ThetaSketchJavaSerializable>> tuple2Iterator = + computeNDVSketches(spark, table.name(), snapshotId, columnList); + Map<String, ThetaSketchJavaSerializable> sketchMap = Maps.newHashMap(); + + tuple2Iterator.forEachRemaining(tuple -> sketchMap.put(tuple._1, tuple._2)); + return writeToPuffin(table, columnList, sketchMap); + } + + private static StatisticsFile writeToPuffin( + Table table, List<String> columns, Map<String, ThetaSketchJavaSerializable> sketchMap) + throws IOException { + TableOperations operations = ((HasTableOperations) table).operations(); + FileIO fileIO = operations.io(); + String path = operations.metadataFileLocation(String.format("%s.stats", UUID.randomUUID())); + OutputFile outputFile = fileIO.newOutputFile(path); + try (PuffinWriter writer = + Puffin.write(outputFile).createdBy("Iceberg Analyze action").build()) { + for (String columnName : columns) { + writer.add( + new Blob( + StandardBlobTypes.APACHE_DATASKETCHES_THETA_V1, + ImmutableList.of(table.schema().findField(columnName).fieldId()), + table.currentSnapshot().snapshotId(), + table.currentSnapshot().sequenceNumber(), + ByteBuffer.wrap(sketchMap.get(columnName).getSketch().toByteArray()), + null, + ImmutableMap.of())); + } + writer.finish(); + + return new GenericStatisticsFile( + table.currentSnapshot().snapshotId(), + path, + writer.fileSize(), + writer.footerSize(), + writer.writtenBlobsMetadata().stream() + .map(GenericBlobMetadata::from) + .collect(ImmutableList.toImmutableList())); + } + } + + static Iterator<Tuple2<String, ThetaSketchJavaSerializable>> computeNDVSketches( + SparkSession spark, String tableName, long snapshotId, List<String> columns) { + Dataset<Row> data = + spark + .read() + .option("snapshot-id", snapshotId) + .table(tableName) + .select(columns.stream().map(functions::col).toArray(Column[]::new)); + + final JavaPairRDD<String, String> pairs = + data.javaRDD() + .flatMap( + row -> { + List<Tuple2<String, String>> columnsList = + Lists.newArrayListWithExpectedSize(columns.size()); + for (int i = 0; i < row.size(); i++) { + columnsList.add(new Tuple2<>(columns.get(i), row.get(i).toString())); + } + return columnsList.iterator(); + }) + .mapToPair(t -> t); + + JavaPairRDD<String, ThetaSketchJavaSerializable> sketches = + pairs.aggregateByKey( + new ThetaSketchJavaSerializable(), + Integer.parseInt( Review Comment: Looks like we may be able to skip passing this , and rely on Spark defaults? Can you do a bit of research to verify? -- 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
