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A table format for huge analytic datasets
/*
* 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.source;
import java.io.IOException;
import java.io.Serializable;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.iceberg.CombinedScanTask;
import org.apache.iceberg.FileFormat;
import org.apache.iceberg.FileScanTask;
import org.apache.iceberg.Schema;
import org.apache.iceberg.SchemaParser;
import org.apache.iceberg.SnapshotSummary;
import org.apache.iceberg.Table;
import org.apache.iceberg.TableProperties;
import org.apache.iceberg.TableScan;
import org.apache.iceberg.encryption.EncryptionManager;
import org.apache.iceberg.exceptions.RuntimeIOException;
import org.apache.iceberg.exceptions.ValidationException;
import org.apache.iceberg.expressions.Expression;
import org.apache.iceberg.expressions.Expressions;
import org.apache.iceberg.hadoop.HadoopFileIO;
import org.apache.iceberg.hadoop.Util;
import org.apache.iceberg.io.CloseableIterable;
import org.apache.iceberg.io.FileIO;
import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
import org.apache.iceberg.relocated.com.google.common.collect.ImmutableSet;
import org.apache.iceberg.relocated.com.google.common.collect.Lists;
import org.apache.iceberg.spark.SparkFilters;
import org.apache.iceberg.spark.SparkSchemaUtil;
import org.apache.iceberg.util.PropertyUtil;
import org.apache.iceberg.util.TableScanUtil;
import org.apache.spark.broadcast.Broadcast;
import org.apache.spark.sql.SparkSession;
import org.apache.spark.sql.catalyst.InternalRow;
import org.apache.spark.sql.sources.Filter;
import org.apache.spark.sql.sources.v2.DataSourceOptions;
import org.apache.spark.sql.sources.v2.reader.DataSourceReader;
import org.apache.spark.sql.sources.v2.reader.InputPartition;
import org.apache.spark.sql.sources.v2.reader.InputPartitionReader;
import org.apache.spark.sql.sources.v2.reader.Statistics;
import org.apache.spark.sql.sources.v2.reader.SupportsPushDownFilters;
import org.apache.spark.sql.sources.v2.reader.SupportsPushDownRequiredColumns;
import org.apache.spark.sql.sources.v2.reader.SupportsReportStatistics;
import org.apache.spark.sql.sources.v2.reader.SupportsScanColumnarBatch;
import org.apache.spark.sql.types.StructType;
import org.apache.spark.sql.vectorized.ColumnarBatch;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static org.apache.iceberg.TableProperties.DEFAULT_NAME_MAPPING;
class Reader implements DataSourceReader, SupportsScanColumnarBatch, SupportsPushDownFilters,
SupportsPushDownRequiredColumns, SupportsReportStatistics {
private static final Logger LOG = LoggerFactory.getLogger(Reader.class);
private static final Filter[] NO_FILTERS = new Filter[0];
private static final ImmutableSet LOCALITY_WHITELIST_FS = ImmutableSet.of("hdfs");
private final Table table;
private final Long snapshotId;
private final Long startSnapshotId;
private final Long endSnapshotId;
private final Long asOfTimestamp;
private final Long splitSize;
private final Integer splitLookback;
private final Long splitOpenFileCost;
private final Broadcast io;
private final Broadcast encryptionManager;
private final boolean caseSensitive;
private StructType requestedSchema = null;
private List filterExpressions = null;
private Filter[] pushedFilters = NO_FILTERS;
private final boolean localityPreferred;
private final boolean batchReadsEnabled;
private final int batchSize;
// lazy variables
private Schema schema = null;
private StructType type = null; // cached because Spark accesses it multiple times
private List tasks = null; // lazy cache of tasks
private Boolean readUsingBatch = null;
Reader(Table table, Broadcast io, Broadcast encryptionManager,
boolean caseSensitive, DataSourceOptions options) {
this.table = table;
this.snapshotId = options.get("snapshot-id").map(Long::parseLong).orElse(null);
this.asOfTimestamp = options.get("as-of-timestamp").map(Long::parseLong).orElse(null);
if (snapshotId != null && asOfTimestamp != null) {
throw new IllegalArgumentException(
"Cannot scan using both snapshot-id and as-of-timestamp to select the table snapshot");
}
this.startSnapshotId = options.get("start-snapshot-id").map(Long::parseLong).orElse(null);
this.endSnapshotId = options.get("end-snapshot-id").map(Long::parseLong).orElse(null);
if (snapshotId != null || asOfTimestamp != null) {
if (startSnapshotId != null || endSnapshotId != null) {
throw new IllegalArgumentException(
"Cannot specify start-snapshot-id and end-snapshot-id to do incremental scan when either snapshot-id or " +
"as-of-timestamp is specified");
}
} else {
if (startSnapshotId == null && endSnapshotId != null) {
throw new IllegalArgumentException("Cannot only specify option end-snapshot-id to do incremental scan");
}
}
// look for split behavior overrides in options
this.splitSize = options.get("split-size").map(Long::parseLong).orElse(null);
this.splitLookback = options.get("lookback").map(Integer::parseInt).orElse(null);
this.splitOpenFileCost = options.get("file-open-cost").map(Long::parseLong).orElse(null);
if (io.getValue() instanceof HadoopFileIO) {
String fsscheme = "no_exist";
try {
Configuration conf = SparkSession.active().sessionState().newHadoopConf();
// merge hadoop config set on table
mergeIcebergHadoopConfs(conf, table.properties());
// merge hadoop config passed as options and overwrite the one on table
mergeIcebergHadoopConfs(conf, options.asMap());
FileSystem fs = new Path(table.location()).getFileSystem(conf);
fsscheme = fs.getScheme().toLowerCase(Locale.ENGLISH);
} catch (IOException ioe) {
LOG.warn("Failed to get Hadoop Filesystem", ioe);
}
String scheme = fsscheme; // Makes an effectively final version of scheme
this.localityPreferred = options.get("locality").map(Boolean::parseBoolean)
.orElseGet(() -> LOCALITY_WHITELIST_FS.contains(scheme));
} else {
this.localityPreferred = false;
}
this.schema = table.schema();
this.io = io;
this.encryptionManager = encryptionManager;
this.caseSensitive = caseSensitive;
this.batchReadsEnabled = options.get("vectorization-enabled").map(Boolean::parseBoolean).orElseGet(() ->
PropertyUtil.propertyAsBoolean(table.properties(),
TableProperties.PARQUET_VECTORIZATION_ENABLED, TableProperties.PARQUET_VECTORIZATION_ENABLED_DEFAULT));
this.batchSize = options.get("batch-size").map(Integer::parseInt).orElseGet(() ->
PropertyUtil.propertyAsInt(table.properties(),
TableProperties.PARQUET_BATCH_SIZE, TableProperties.PARQUET_BATCH_SIZE_DEFAULT));
}
private Schema lazySchema() {
if (schema == null) {
if (requestedSchema != null) {
// the projection should include all columns that will be returned, including those only used in filters
this.schema = SparkSchemaUtil.prune(table.schema(), requestedSchema, filterExpression(), caseSensitive);
} else {
this.schema = table.schema();
}
}
return schema;
}
private Expression filterExpression() {
if (filterExpressions != null) {
return filterExpressions.stream().reduce(Expressions.alwaysTrue(), Expressions::and);
}
return Expressions.alwaysTrue();
}
private StructType lazyType() {
if (type == null) {
this.type = SparkSchemaUtil.convert(lazySchema());
}
return type;
}
@Override
public StructType readSchema() {
return lazyType();
}
/**
* This is called in the Spark Driver when data is to be materialized into {@link ColumnarBatch}
*/
@Override
public List> planBatchInputPartitions() {
Preconditions.checkState(enableBatchRead(), "Batched reads not enabled");
Preconditions.checkState(batchSize > 0, "Invalid batch size");
String tableSchemaString = SchemaParser.toJson(table.schema());
String expectedSchemaString = SchemaParser.toJson(lazySchema());
String nameMappingString = table.properties().get(DEFAULT_NAME_MAPPING);
ValidationException.check(tasks().stream().noneMatch(TableScanUtil::hasDeletes),
"Cannot scan table %s: cannot apply required delete files", table);
List> readTasks = Lists.newArrayList();
for (CombinedScanTask task : tasks()) {
readTasks.add(new ReadTask<>(
task, tableSchemaString, expectedSchemaString, nameMappingString, io, encryptionManager, caseSensitive,
localityPreferred, new BatchReaderFactory(batchSize)));
}
LOG.info("Batching input partitions with {} tasks.", readTasks.size());
return readTasks;
}
/**
* This is called in the Spark Driver when data is to be materialized into {@link InternalRow}
*/
@Override
public List> planInputPartitions() {
String tableSchemaString = SchemaParser.toJson(table.schema());
String expectedSchemaString = SchemaParser.toJson(lazySchema());
String nameMappingString = table.properties().get(DEFAULT_NAME_MAPPING);
List> readTasks = Lists.newArrayList();
for (CombinedScanTask task : tasks()) {
readTasks.add(new ReadTask<>(
task, tableSchemaString, expectedSchemaString, nameMappingString, io, encryptionManager, caseSensitive,
localityPreferred, InternalRowReaderFactory.INSTANCE));
}
return readTasks;
}
@Override
public Filter[] pushFilters(Filter[] filters) {
this.tasks = null; // invalidate cached tasks, if present
List expressions = Lists.newArrayListWithExpectedSize(filters.length);
List pushed = Lists.newArrayListWithExpectedSize(filters.length);
for (Filter filter : filters) {
Expression expr = SparkFilters.convert(filter);
if (expr != null) {
expressions.add(expr);
pushed.add(filter);
}
}
this.filterExpressions = expressions;
this.pushedFilters = pushed.toArray(new Filter[0]);
// invalidate the schema that will be projected
this.schema = null;
this.type = null;
// Spark doesn't support residuals per task, so return all filters
// to get Spark to handle record-level filtering
return filters;
}
@Override
public Filter[] pushedFilters() {
return pushedFilters;
}
@Override
public void pruneColumns(StructType newRequestedSchema) {
this.requestedSchema = newRequestedSchema;
// invalidate the schema that will be projected
this.schema = null;
this.type = null;
}
@Override
public Statistics estimateStatistics() {
// its a fresh table, no data
if (table.currentSnapshot() == null) {
return new Stats(0L, 0L);
}
// estimate stats using snapshot summary only for partitioned tables (metadata tables are unpartitioned)
if (!table.spec().isUnpartitioned() && filterExpression() == Expressions.alwaysTrue()) {
long totalRecords = PropertyUtil.propertyAsLong(table.currentSnapshot().summary(),
SnapshotSummary.TOTAL_RECORDS_PROP, Long.MAX_VALUE);
return new Stats(SparkSchemaUtil.estimateSize(lazyType(), totalRecords), totalRecords);
}
long sizeInBytes = 0L;
long numRows = 0L;
for (CombinedScanTask task : tasks()) {
for (FileScanTask file : task.files()) {
sizeInBytes += file.length();
numRows += file.file().recordCount();
}
}
return new Stats(sizeInBytes, numRows);
}
@Override
public boolean enableBatchRead() {
if (readUsingBatch == null) {
boolean allParquetFileScanTasks =
tasks().stream()
.allMatch(combinedScanTask -> !combinedScanTask.isDataTask() && combinedScanTask.files()
.stream()
.allMatch(fileScanTask -> fileScanTask.file().format().equals(
FileFormat.PARQUET)));
boolean allOrcFileScanTasks =
tasks().stream()
.allMatch(combinedScanTask -> !combinedScanTask.isDataTask() && combinedScanTask.files()
.stream()
.allMatch(fileScanTask -> fileScanTask.file().format().equals(
FileFormat.ORC)));
boolean atLeastOneColumn = lazySchema().columns().size() > 0;
boolean onlyPrimitives = lazySchema().columns().stream().allMatch(c -> c.type().isPrimitiveType());
boolean hasNoDeleteFiles = tasks().stream().noneMatch(TableScanUtil::hasDeletes);
this.readUsingBatch = batchReadsEnabled && hasNoDeleteFiles && (allOrcFileScanTasks ||
(allParquetFileScanTasks && atLeastOneColumn && onlyPrimitives));
}
return readUsingBatch;
}
private static void mergeIcebergHadoopConfs(
Configuration baseConf, Map options) {
options.keySet().stream()
.filter(key -> key.startsWith("hadoop."))
.forEach(key -> baseConf.set(key.replaceFirst("hadoop.", ""), options.get(key)));
}
private List tasks() {
if (tasks == null) {
TableScan scan = table
.newScan()
.caseSensitive(caseSensitive)
.project(lazySchema());
if (snapshotId != null) {
scan = scan.useSnapshot(snapshotId);
}
if (asOfTimestamp != null) {
scan = scan.asOfTime(asOfTimestamp);
}
if (startSnapshotId != null) {
if (endSnapshotId != null) {
scan = scan.appendsBetween(startSnapshotId, endSnapshotId);
} else {
scan = scan.appendsAfter(startSnapshotId);
}
}
if (splitSize != null) {
scan = scan.option(TableProperties.SPLIT_SIZE, splitSize.toString());
}
if (splitLookback != null) {
scan = scan.option(TableProperties.SPLIT_LOOKBACK, splitLookback.toString());
}
if (splitOpenFileCost != null) {
scan = scan.option(TableProperties.SPLIT_OPEN_FILE_COST, splitOpenFileCost.toString());
}
if (filterExpressions != null) {
for (Expression filter : filterExpressions) {
scan = scan.filter(filter);
}
}
try (CloseableIterable tasksIterable = scan.planTasks()) {
this.tasks = Lists.newArrayList(tasksIterable);
} catch (IOException e) {
throw new RuntimeIOException(e, "Failed to close table scan: %s", scan);
}
}
return tasks;
}
@Override
public String toString() {
return String.format(
"IcebergScan(table=%s, type=%s, filters=%s, caseSensitive=%s, batchedReads=%s)",
table, lazySchema().asStruct(), filterExpressions, caseSensitive, enableBatchRead());
}
private static class ReadTask implements Serializable, InputPartition {
private final CombinedScanTask task;
private final String tableSchemaString;
private final String expectedSchemaString;
private final String nameMappingString;
private final Broadcast io;
private final Broadcast encryptionManager;
private final boolean caseSensitive;
private final boolean localityPreferred;
private final ReaderFactory readerFactory;
private transient Schema tableSchema = null;
private transient Schema expectedSchema = null;
private transient String[] preferredLocations = null;
private ReadTask(CombinedScanTask task, String tableSchemaString, String expectedSchemaString,
String nameMappingString, Broadcast io, Broadcast encryptionManager,
boolean caseSensitive, boolean localityPreferred, ReaderFactory readerFactory) {
this.task = task;
this.tableSchemaString = tableSchemaString;
this.expectedSchemaString = expectedSchemaString;
this.io = io;
this.encryptionManager = encryptionManager;
this.caseSensitive = caseSensitive;
this.localityPreferred = localityPreferred;
this.preferredLocations = getPreferredLocations();
this.readerFactory = readerFactory;
this.nameMappingString = nameMappingString;
}
@Override
public InputPartitionReader createPartitionReader() {
return readerFactory.create(task, lazyTableSchema(), lazyExpectedSchema(), nameMappingString, io.value(),
encryptionManager.value(), caseSensitive);
}
@Override
public String[] preferredLocations() {
return preferredLocations;
}
private Schema lazyTableSchema() {
if (tableSchema == null) {
this.tableSchema = SchemaParser.fromJson(tableSchemaString);
}
return tableSchema;
}
private Schema lazyExpectedSchema() {
if (expectedSchema == null) {
this.expectedSchema = SchemaParser.fromJson(expectedSchemaString);
}
return expectedSchema;
}
@SuppressWarnings("checkstyle:RegexpSingleline")
private String[] getPreferredLocations() {
if (!localityPreferred) {
return new String[0];
}
Configuration conf = SparkSession.active().sparkContext().hadoopConfiguration();
return Util.blockLocations(task, conf);
}
}
private interface ReaderFactory extends Serializable {
InputPartitionReader create(CombinedScanTask task, Schema tableSchema, Schema expectedSchema,
String nameMapping, FileIO io,
EncryptionManager encryptionManager, boolean caseSensitive);
}
private static class InternalRowReaderFactory implements ReaderFactory {
private static final InternalRowReaderFactory INSTANCE = new InternalRowReaderFactory();
private InternalRowReaderFactory() {
}
@Override
public InputPartitionReader create(CombinedScanTask task, Schema tableSchema, Schema expectedSchema,
String nameMapping, FileIO io,
EncryptionManager encryptionManager, boolean caseSensitive) {
return new RowReader(task, tableSchema, expectedSchema, nameMapping, io, encryptionManager, caseSensitive);
}
}
private static class BatchReaderFactory implements ReaderFactory {
private final int batchSize;
BatchReaderFactory(int batchSize) {
this.batchSize = batchSize;
}
@Override
public InputPartitionReader create(CombinedScanTask task, Schema tableSchema, Schema expectedSchema,
String nameMapping, FileIO io,
EncryptionManager encryptionManager, boolean caseSensitive) {
return new BatchReader(task, expectedSchema, nameMapping, io, encryptionManager, caseSensitive, batchSize);
}
}
private static class RowReader extends RowDataReader implements InputPartitionReader {
RowReader(CombinedScanTask task, Schema tableSchema, Schema expectedSchema, String nameMapping, FileIO io,
EncryptionManager encryptionManager, boolean caseSensitive) {
super(task, tableSchema, expectedSchema, nameMapping, io, encryptionManager, caseSensitive);
}
}
private static class BatchReader extends BatchDataReader implements InputPartitionReader {
BatchReader(CombinedScanTask task, Schema expectedSchema, String nameMapping, FileIO io,
EncryptionManager encryptionManager, boolean caseSensitive, int size) {
super(task, expectedSchema, nameMapping, io, encryptionManager, caseSensitive, size);
}
}
}
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