org.apache.hadoop.mapreduce.lib.db.MySQLDataDrivenDBRecordReader.java Source code

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Here is the source code for org.apache.hadoop.mapreduce.lib.db.MySQLDataDrivenDBRecordReader.java

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/**
 * 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.hadoop.mapreduce.lib.db;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.PreparedStatement;
import java.sql.SQLException;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;

/**
 * A RecordReader that reads records from a MySQL table via DataDrivenDBRecordReader
 */
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class MySQLDataDrivenDBRecordReader<T extends DBWritable> extends DataDrivenDBRecordReader<T> {

    public MySQLDataDrivenDBRecordReader(DBInputFormat.DBInputSplit split, Class<T> inputClass, Configuration conf,
            Connection conn, DBConfiguration dbConfig, String cond, String[] fields, String table)
            throws SQLException {
        super(split, inputClass, conf, conn, dbConfig, cond, fields, table, "MYSQL");
    }

    // Execute statements for mysql in unbuffered mode.
    protected ResultSet executeQuery(String query) throws SQLException {
        statement = getConnection().prepareStatement(query, ResultSet.TYPE_FORWARD_ONLY,
                ResultSet.CONCUR_READ_ONLY);
        statement.setFetchSize(Integer.MIN_VALUE); // MySQL: read row-at-a-time.
        return statement.executeQuery();
    }
}