dramaticlly commented on code in PR #11106: URL: https://github.com/apache/iceberg/pull/11106#discussion_r1755572668
########## spark/v3.4/spark/src/main/java/org/apache/iceberg/spark/actions/NDVSketchUtil.java: ########## @@ -0,0 +1,93 @@ +/* + * 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.nio.ByteBuffer; +import java.util.List; +import org.apache.datasketches.memory.Memory; +import org.apache.datasketches.theta.CompactSketch; +import org.apache.datasketches.theta.Sketch; +import org.apache.iceberg.Schema; +import org.apache.iceberg.Snapshot; +import org.apache.iceberg.Table; +import org.apache.iceberg.puffin.Blob; +import org.apache.iceberg.puffin.PuffinCompressionCodec; +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.spark.SparkReadOptions; +import org.apache.iceberg.types.Types; +import org.apache.spark.sql.Column; +import org.apache.spark.sql.Row; +import org.apache.spark.sql.SparkSession; +import org.apache.spark.sql.stats.ThetaSketchAgg; + +public class NDVSketchUtil { + + private NDVSketchUtil() {} + + public static final String APACHE_DATASKETCHES_THETA_V1_NDV_PROPERTY = "ndv"; + + static List<Blob> generateBlobs( + SparkSession spark, Table table, Snapshot snapshot, List<String> columns) { + Row sketches = computeNDVSketches(spark, table, snapshot, columns); + Schema schema = table.schemas().get(snapshot.schemaId()); + List<Blob> blobs = Lists.newArrayList(); + for (int i = 0; i < columns.size(); i++) { + Types.NestedField field = schema.findField(columns.get(i)); + Sketch sketch = CompactSketch.wrap(Memory.wrap((byte[]) sketches.get(i))); + blobs.add(toBlob(field, sketch, snapshot)); + } + return blobs; + } + + private static Blob toBlob(Types.NestedField field, Sketch sketch, Snapshot snapshot) { + return new Blob( + StandardBlobTypes.APACHE_DATASKETCHES_THETA_V1, + ImmutableList.of(field.fieldId()), + snapshot.snapshotId(), + snapshot.sequenceNumber(), + ByteBuffer.wrap(sketch.toByteArray()), + PuffinCompressionCodec.ZSTD, + ImmutableMap.of( + APACHE_DATASKETCHES_THETA_V1_NDV_PROPERTY, + String.valueOf((long) sketch.getEstimate()))); + } + + private static Row computeNDVSketches( + SparkSession spark, Table table, Snapshot snapshot, List<String> colNames) { + return spark + .read() + .format("iceberg") + .option(SparkReadOptions.SNAPSHOT_ID, snapshot.snapshotId()) + .load(table.name()) + .select(toAggColumns(colNames)) + .first(); Review Comment: do we need backport #10984 for spark 3.4 as well per Anton's comment in https://github.com/apache/iceberg/pull/10288/files#r1726000959? Happy to help -- 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
