com.pivotal.hawq.mapreduce.ao.HAWQAOInputFormat.java Source code

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Here is the source code for com.pivotal.hawq.mapreduce.ao.HAWQAOInputFormat.java

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package com.pivotal.hawq.mapreduce.ao;

/*
 * 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.
 */

import com.pivotal.hawq.mapreduce.HAWQRecord;
import com.pivotal.hawq.mapreduce.file.HAWQAOFileStatus;
import com.pivotal.hawq.mapreduce.ao.file.HAWQAOSplit;
import com.pivotal.hawq.mapreduce.conf.HAWQConfiguration;

import com.pivotal.hawq.mapreduce.metadata.HAWQAOTableMetadata;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
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.FileInputFormat;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * An InputFormat that reads input data from HAWQ append only table.
 *<p>
 * In most cases, you should consider use HAWQInputFormat, which delegates to
 * this class for AO table, but can handle other non-AO table as well.
 */
public final class HAWQAOInputFormat extends FileInputFormat<Void, HAWQRecord> {
    private static final Log LOG = LogFactory.getLog(HAWQAOInputFormat.class);

    private static HAWQAOFileStatus[] fileStatuses = null;

    /**
     * Initializes the map-part of the job with the appropriate input settings
     * through connecting to Database.
     * 
     * @param conf
     *            The map-reduce job configuration
     * @param metadata
     *            The metadata of this table get from database or metadataFile
     */
    public static void setInput(Configuration conf, HAWQAOTableMetadata metadata) {
        HAWQConfiguration.setInputTableEncoding(conf, metadata.getDatabaseEncoding());
        HAWQConfiguration.setInputTableSchema(conf, metadata.getSchema());
        /*
         * GPSQL-1047
         * 
         * Set version into configuration to get working environment of database
         */
        HAWQConfiguration.setDatabaseVersion(conf, metadata.getDatabaseVersion());
        fileStatuses = metadata.getFileStatuses();
    }

    /**
     * Create a record reader for a given split. The framework will call
     * {@link RecordReader#initialize(InputSplit, TaskAttemptContext)} before
     * the split is used.
     * 
     * @param split
     *            the split to be read
     * @param context
     *            the information about the task
     * @return a new record reader
     * @throws IOException
     * @throws InterruptedException
     */
    @Override
    public RecordReader<Void, HAWQRecord> createRecordReader(InputSplit split, TaskAttemptContext context)
            throws IOException, InterruptedException {
        // For AO table, we return HAWQAORecordReader
        RecordReader<Void, HAWQRecord> recordReader = new HAWQAORecordReader();
        return recordReader;
    }

    /**
     * Generate the list of files and make them into FileSplits.
     * 
     * @param job
     *            the job context
     * @throws IOException
     */
    @Override
    public List<InputSplit> getSplits(JobContext job) throws IOException {
        List<InputSplit> splits = new ArrayList<InputSplit>();
        for (int i = 0; i < fileStatuses.length; ++i) {
            HAWQAOFileStatus aofilestatus = fileStatuses[i];
            String pathStr = aofilestatus.getFilePath();
            long fileLength = aofilestatus.getFileLength();
            if (fileLength == 0)
                continue;

            boolean checksum = aofilestatus.getChecksum();
            String compressType = aofilestatus.getCompressType();
            int blocksize = aofilestatus.getBlockSize();
            Path path = new Path(pathStr);
            if (fileLength != 0) {
                FileSystem fs = path.getFileSystem(job.getConfiguration());
                BlockLocation[] blkLocations = fs.getFileBlockLocations(fs.getFileStatus(path), 0, fileLength);
                // not splitable
                splits.add(new HAWQAOSplit(path, 0, fileLength, blkLocations[0].getHosts(), checksum, compressType,
                        blocksize));
            } else {
                // Create empty hosts array for zero length files
                splits.add(new HAWQAOSplit(path, 0, fileLength, new String[0], checksum, compressType, blocksize));
            }
        }
        job.getConfiguration().setLong(NUM_INPUT_FILES, splits.size());
        LOG.debug("Total # of splits: " + splits.size());
        return splits;
    }

}