aokolnychyi commented on a change in pull request #805: Add all_data_files, all_manifests, and all_entries metadata tables URL: https://github.com/apache/incubator-iceberg/pull/805#discussion_r382711734
########## File path: core/src/main/java/org/apache/iceberg/AllDataFilesTable.java ########## @@ -0,0 +1,149 @@ +/* + * 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; + +import com.google.common.collect.ImmutableMap; +import com.google.common.collect.Iterables; +import com.google.common.collect.Sets; +import java.io.IOException; +import java.util.Collection; +import java.util.List; +import org.apache.iceberg.exceptions.RuntimeIOException; +import org.apache.iceberg.expressions.Expression; +import org.apache.iceberg.expressions.ResidualEvaluator; +import org.apache.iceberg.io.CloseableIterable; +import org.apache.iceberg.types.TypeUtil; +import org.apache.iceberg.util.ParallelIterable; +import org.apache.iceberg.util.ThreadPools; + +/** + * A {@link Table} implementation that exposes a table's valid data files as rows. + * <p> + * A valid data file is one that is readable from any snapshot currently tracked by the table. + * <p> + * This table may return duplicate rows. + */ +public class AllDataFilesTable extends BaseMetadataTable { + private final TableOperations ops; + private final Table table; + + public AllDataFilesTable(TableOperations ops, Table table) { + this.ops = ops; + this.table = table; + } + + @Override + Table table() { + return table; + } + + @Override + String metadataTableName() { + return "all_data_files"; + } + + @Override + public TableScan newScan() { + return new AllDataFilesTableScan(ops, table, schema()); + } + + @Override + public Schema schema() { + Schema schema = new Schema(DataFile.getType(table.spec().partitionType()).fields()); + if (table.spec().fields().size() < 1) { + // avoid returning an empty struct, which is not always supported. instead, drop the partition field (id 102) + return TypeUtil.selectNot(schema, Sets.newHashSet(102)); + } else { + return schema; + } + } + + @Override + public String location() { + return table.currentSnapshot().manifestListLocation(); + } + + public static class AllDataFilesTableScan extends BaseTableScan { + private static final long TARGET_SPLIT_SIZE = 32 * 1024 * 1024; // 32 MB + private final Schema fileSchema; + + AllDataFilesTableScan(TableOperations ops, Table table, Schema fileSchema) { + super(ops, table, fileSchema); + this.fileSchema = fileSchema; + } + + private AllDataFilesTableScan( + TableOperations ops, Table table, Long snapshotId, Schema schema, Expression rowFilter, + boolean caseSensitive, boolean colStats, Collection<String> selectedColumns, Schema fileSchema, + ImmutableMap<String, String> options) { + super(ops, table, snapshotId, schema, rowFilter, caseSensitive, colStats, selectedColumns, options); + this.fileSchema = fileSchema; + } + + @Override + protected TableScan newRefinedScan( + TableOperations ops, Table table, Long snapshotId, Schema schema, Expression rowFilter, + boolean caseSensitive, boolean colStats, Collection<String> selectedColumns, + ImmutableMap<String, String> options) { + return new AllDataFilesTableScan( + ops, table, snapshotId, schema, rowFilter, caseSensitive, colStats, selectedColumns, fileSchema, options); + } + + @Override + public TableScan useSnapshot(long scanSnapshotId) { + throw new UnsupportedOperationException("Cannot select snapshot: all_data_files is for all snapshots"); + } + + @Override + public TableScan asOfTime(long timestampMillis) { + throw new UnsupportedOperationException("Cannot select snapshot: all_data_files is for all snapshots"); + } + + @Override + protected long targetSplitSize(TableOperations ops) { + return TARGET_SPLIT_SIZE; + } + + @Override + protected CloseableIterable<FileScanTask> planFiles( + TableOperations ops, Snapshot snapshot, Expression rowFilter, boolean caseSensitive, boolean colStats) { + CloseableIterable<ManifestFile> manifests = allManifestFiles(ops.current().snapshots()); + String schemaString = SchemaParser.toJson(schema()); + String specString = PartitionSpecParser.toJson(PartitionSpec.unpartitioned()); + ResidualEvaluator residuals = ResidualEvaluator.unpartitioned(rowFilter); + + // Data tasks produce the table schema, not the projection schema and projection is done by processing engines. + // This data task needs to use the table schema, which may not include a partition schema to avoid having an + // empty struct in the schema for unpartitioned tables. Some engines, like Spark, can't handle empty structs in + // all cases. + return CloseableIterable.transform(manifests, manifest -> + new DataFilesTable.ManifestReadTask(ops.io(), manifest, fileSchema, schemaString, specString, residuals)); + } + } + + static CloseableIterable<ManifestFile> allManifestFiles(List<Snapshot> snapshots) { Review comment: There are a couple of places when we define static methods in one metadata table class and call them in others. It seems we can put some of those in the parent `BaseMetadataTable`. ---------------------------------------------------------------- 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. 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