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A table format for huge analytic datasets
There is a newer version: 1.7.1
/*
 * 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 java.util.Map;
import org.apache.iceberg.expressions.Expression;
import org.apache.iceberg.expressions.Expressions;
import org.apache.iceberg.expressions.ResidualEvaluator;
import org.apache.iceberg.io.CloseableIterable;
import org.apache.iceberg.io.FileIO;
import org.apache.iceberg.relocated.com.google.common.collect.ImmutableList;
import org.apache.iceberg.relocated.com.google.common.collect.Maps;
import org.apache.iceberg.relocated.com.google.common.collect.Sets;
import org.apache.iceberg.types.Type;
import org.apache.iceberg.types.TypeUtil;
import org.apache.iceberg.types.Types.StructType;
import org.apache.iceberg.util.StructProjection;

/**
 * A {@link Table} implementation that exposes a table's manifest entries as rows, for both delete
 * and data files.
 *
 * WARNING: this table exposes internal details, like files that have been deleted. For a table
 * of the live data files, use {@link DataFilesTable}.
 */
public class ManifestEntriesTable extends BaseMetadataTable {

  ManifestEntriesTable(TableOperations ops, Table table) {
    this(ops, table, table.name() + ".entries");
  }

  ManifestEntriesTable(TableOperations ops, Table table, String name) {
    super(ops, table, name);
  }

  @Override
  public TableScan newScan() {
    return new EntriesTableScan(operations(), table(), schema());
  }

  @Override
  public Schema schema() {
    StructType partitionType = Partitioning.partitionType(table());
    Schema schema = ManifestEntry.getSchema(partitionType);
    if (partitionType.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
  MetadataTableType metadataTableType() {
    return MetadataTableType.ENTRIES;
  }

  private static class EntriesTableScan extends BaseMetadataTableScan {

    EntriesTableScan(TableOperations ops, Table table, Schema schema) {
      super(ops, table, schema, MetadataTableType.ENTRIES);
    }

    private EntriesTableScan(
        TableOperations ops, Table table, Schema schema, TableScanContext context) {
      super(ops, table, schema, MetadataTableType.ENTRIES, context);
    }

    @Override
    protected TableScan newRefinedScan(
        TableOperations ops, Table table, Schema schema, TableScanContext context) {
      return new EntriesTableScan(ops, table, schema, context);
    }

    @Override
    protected CloseableIterable doPlanFiles() {
      // return entries from both data and delete manifests
      CloseableIterable manifests =
          CloseableIterable.withNoopClose(snapshot().allManifests(tableOps().io()));
      String schemaString = SchemaParser.toJson(schema());
      String specString = PartitionSpecParser.toJson(PartitionSpec.unpartitioned());
      Expression filter = shouldIgnoreResiduals() ? Expressions.alwaysTrue() : filter();
      ResidualEvaluator residuals = ResidualEvaluator.unpartitioned(filter);

      return CloseableIterable.transform(
          manifests,
          manifest ->
              new ManifestReadTask(
                  table(), manifest, schema(), schemaString, specString, residuals));
    }
  }

  static class ManifestReadTask extends BaseFileScanTask implements DataTask {
    private final Schema schema;
    private final Schema fileSchema;
    private final FileIO io;
    private final ManifestFile manifest;
    private final Map specsById;

    ManifestReadTask(
        Table table,
        ManifestFile manifest,
        Schema schema,
        String schemaString,
        String specString,
        ResidualEvaluator residuals) {
      super(DataFiles.fromManifest(manifest), null, schemaString, specString, residuals);
      this.schema = schema;
      this.io = table.io();
      this.manifest = manifest;
      this.specsById = Maps.newHashMap(table.specs());

      Type fileProjection = schema.findType("data_file");
      this.fileSchema =
          fileProjection != null
              ? new Schema(fileProjection.asStructType().fields())
              : new Schema();
    }

    @Override
    public CloseableIterable rows() {
      // Project data-file fields
      CloseableIterable prunedRows;
      if (manifest.content() == ManifestContent.DATA) {
        prunedRows =
            CloseableIterable.transform(
                ManifestFiles.read(manifest, io).project(fileSchema).entries(),
                file -> (GenericManifestEntry) file);
      } else {
        prunedRows =
            CloseableIterable.transform(
                ManifestFiles.readDeleteManifest(manifest, io, specsById)
                    .project(fileSchema)
                    .entries(),
                file -> (GenericManifestEntry) file);
      }

      // Project non-readable fields
      Schema readSchema = ManifestEntry.wrapFileSchema(fileSchema.asStruct());
      StructProjection projection = StructProjection.create(readSchema, schema);
      return CloseableIterable.transform(prunedRows, projection::wrap);
    }

    @Override
    public Iterable split(long splitSize) {
      return ImmutableList.of(this); // don't split
    }
  }
}