/**
* 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
* <p/>
* http://www.apache.org/licenses/LICENSE-2.0
* <p/>
* 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 parquet.hadoop;
import static parquet.filter2.compat.RowGroupFilter.filterRowGroups;
import static parquet.format.converter.ParquetMetadataConverter.NO_FILTER;
import static parquet.format.converter.ParquetMetadataConverter.range;
import static parquet.hadoop.ParquetFileReader.readFooter;
import static parquet.hadoop.ParquetInputFormat.getFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.TaskInputOutputContext;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import parquet.Log;
import parquet.filter.UnboundRecordFilter;
import parquet.filter2.compat.FilterCompat;
import parquet.filter2.compat.FilterCompat.Filter;
import parquet.hadoop.api.ReadSupport;
import parquet.hadoop.metadata.BlockMetaData;
import parquet.hadoop.metadata.ParquetMetadata;
import parquet.hadoop.util.ContextUtil;
import parquet.hadoop.util.counters.BenchmarkCounter;
import parquet.schema.MessageType;
/**
* Reads the records from a block of a Parquet file
*
* @see ParquetInputFormat
*
* @author Julien Le Dem
*
* @param <T> type of the materialized records
*/
public class ParquetRecordReader<T> extends RecordReader<Void, T> {
private static final Log LOG = Log.getLog(ParquetRecordReader.class);
private final InternalParquetRecordReader<T> internalReader;
/**
* @param readSupport Object which helps reads files of the given type, e.g. Thrift, Avro.
*/
public ParquetRecordReader(ReadSupport<T> readSupport) {
this(readSupport, FilterCompat.NOOP);
}
/**
* @param readSupport Object which helps reads files of the given type, e.g. Thrift, Avro.
* @param filter for filtering individual records
*/
public ParquetRecordReader(ReadSupport<T> readSupport, Filter filter) {
internalReader = new InternalParquetRecordReader<T>(readSupport, filter);
}
/**
* @param readSupport Object which helps reads files of the given type, e.g. Thrift, Avro.
* @param filter for filtering individual records
* @deprecated use {@link #ParquetRecordReader(ReadSupport, Filter)}
*/
@Deprecated
public ParquetRecordReader(ReadSupport<T> readSupport, UnboundRecordFilter filter) {
this(readSupport, FilterCompat.get(filter));
}
/**
* {@inheritDoc}
*/
@Override
public void close() throws IOException {
internalReader.close();
}
/**
* always returns null
*/
@Override
public Void getCurrentKey() throws IOException, InterruptedException {
return null;
}
/**
* {@inheritDoc}
*/
@Override
public T getCurrentValue() throws IOException,
InterruptedException {
return internalReader.getCurrentValue();
}
/**
* {@inheritDoc}
*/
@Override
public float getProgress() throws IOException, InterruptedException {
return internalReader.getProgress();
}
/**
* {@inheritDoc}
*/
@Override
public void initialize(InputSplit inputSplit, TaskAttemptContext context)
throws IOException, InterruptedException {
if (context instanceof TaskInputOutputContext<?, ?, ?, ?>) {
BenchmarkCounter.initCounterFromContext((TaskInputOutputContext<?, ?, ?, ?>) context);
} else {
LOG.error("Can not initialize counter due to context is not a instance of TaskInputOutputContext, but is "
+ context.getClass().getCanonicalName());
}
initializeInternalReader(toParquetSplit(inputSplit), ContextUtil.getConfiguration(context));
}
public void initialize(InputSplit inputSplit, Configuration configuration, Reporter reporter)
throws IOException, InterruptedException {
BenchmarkCounter.initCounterFromReporter(reporter, configuration);
initializeInternalReader(toParquetSplit(inputSplit), configuration);
}
private void initializeInternalReader(ParquetInputSplit split, Configuration configuration) throws IOException {
Path path = split.getPath();
long[] rowGroupOffsets = split.getRowGroupOffsets();
List<BlockMetaData> filteredBlocks;
ParquetMetadata footer;
// if task.side.metadata is set, rowGroupOffsets is null
if (rowGroupOffsets == null) {
// then we need to apply the predicate push down filter
footer = readFooter(configuration, path, range(split.getStart(), split.getEnd()));
MessageType fileSchema = footer.getFileMetaData().getSchema();
Filter filter = getFilter(configuration);
filteredBlocks = filterRowGroups(filter, footer.getBlocks(), fileSchema);
} else {
// otherwise we find the row groups that were selected on the client
footer = readFooter(configuration, path, NO_FILTER);
Set<Long> offsets = new HashSet<Long>();
for (long offset : rowGroupOffsets) {
offsets.add(offset);
}
filteredBlocks = new ArrayList<BlockMetaData>();
for (BlockMetaData block : footer.getBlocks()) {
if (offsets.contains(block.getStartingPos())) {
filteredBlocks.add(block);
}
}
// verify we found them all
if (filteredBlocks.size() != rowGroupOffsets.length) {
long[] foundRowGroupOffsets = new long[footer.getBlocks().size()];
for (int i = 0; i < foundRowGroupOffsets.length; i++) {
foundRowGroupOffsets[i] = footer.getBlocks().get(i).getStartingPos();
}
// this should never happen.
// provide a good error message in case there's a bug
throw new IllegalStateException(
"All the offsets listed in the split should be found in the file."
+ " expected: " + Arrays.toString(rowGroupOffsets)
+ " found: " + filteredBlocks
+ " out of: " + Arrays.toString(foundRowGroupOffsets)
+ " in range " + split.getStart() + ", " + split.getEnd());
}
}
MessageType fileSchema = footer.getFileMetaData().getSchema();
Map<String, String> fileMetaData = footer.getFileMetaData().getKeyValueMetaData();
internalReader.initialize(
fileSchema, fileMetaData, path, filteredBlocks, configuration);
}
/**
* {@inheritDoc}
*/
@Override
public boolean nextKeyValue() throws IOException, InterruptedException {
return internalReader.nextKeyValue();
}
private ParquetInputSplit toParquetSplit(InputSplit split) throws IOException {
if (split instanceof ParquetInputSplit) {
return (ParquetInputSplit) split;
} else if (split instanceof FileSplit) {
return ParquetInputSplit.from((FileSplit) split);
} else if (split instanceof org.apache.hadoop.mapred.FileSplit) {
return ParquetInputSplit.from(
(org.apache.hadoop.mapred.FileSplit) split);
} else {
throw new IllegalArgumentException(
"Invalid split (not a FileSplit or ParquetInputSplit): " + split);
}
}
}