/**
* 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.sqoop.mapreduce;
import java.io.IOException;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.CombineFileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.CombineFileRecordReader;
import org.apache.hadoop.mapreduce.lib.input.CombineFileSplit;
/**
* InputFormat that generates a user-defined number of splits to inject data
* into the database.
*/
public class ExportInputFormat
extends CombineFileInputFormat<LongWritable, Object> {
public static final Log LOG =
LogFactory.getLog(ExportInputFormat.class.getName());
public static final int DEFAULT_NUM_MAP_TASKS = 4;
public ExportInputFormat() {
}
/**
* @return the number of bytes across all files in the job.
*/
private long getJobSize(JobContext job) throws IOException {
List<FileStatus> stats = listStatus(job);
long count = 0;
for (FileStatus stat : stats) {
count += stat.getLen();
}
return count;
}
@Override
public List<InputSplit> getSplits(JobContext job) throws IOException {
// Set the max split size based on the number of map tasks we want.
long numTasks = getNumMapTasks(job);
long numFileBytes = getJobSize(job);
long maxSplitSize = numFileBytes / numTasks;
setMaxSplitSize(maxSplitSize);
LOG.debug("Target numMapTasks=" + numTasks);
LOG.debug("Total input bytes=" + numFileBytes);
LOG.debug("maxSplitSize=" + maxSplitSize);
List<InputSplit> splits = super.getSplits(job);
if (LOG.isDebugEnabled()) {
LOG.debug("Generated splits:");
for (InputSplit split : splits) {
LOG.debug(" " + split);
}
}
return splits;
}
@Override
@SuppressWarnings("unchecked")
public RecordReader createRecordReader(
InputSplit split, TaskAttemptContext context) throws IOException {
CombineFileSplit combineSplit = (CombineFileSplit) split;
// Use CombineFileRecordReader since this can handle CombineFileSplits
// and instantiate another RecordReader in a loop; do this with the
// CombineShimRecordReader.
RecordReader rr = new CombineFileRecordReader(combineSplit, context,
CombineShimRecordReader.class);
return rr;
}
/**
* Allows the user to control the number of map tasks used for this
* export job.
*/
public static void setNumMapTasks(JobContext job, int numTasks) {
job.getConfiguration().setInt(ExportJobBase.EXPORT_MAP_TASKS_KEY, numTasks);
}
/**
* @return the number of map tasks to use in this export job.
*/
public static int getNumMapTasks(JobContext job) {
return job.getConfiguration().getInt(ExportJobBase.EXPORT_MAP_TASKS_KEY,
DEFAULT_NUM_MAP_TASKS);
}
}