[
https://issues.apache.org/jira/browse/SQOOP-1312?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jarek Jarcec Cecho updated SQOOP-1312:
--------------------------------------
Description:
When we used Sqoop to load data from mySQL using one double column as split-key
in Samsung SDS,
the last mapper did not load data from mySQL at all.
The number of mappers was sometimes increased by 1.
I think they were caused by some bugs in FloatSplitter.java
For the last split, lowClausePrefix + Double.toString(curUpper), may be
lowClausePrefix + Double.toString(curLower).
In while (curUpper < maxVal) loop, because of round-off error,
minVal + splitSize * numSplits can be smaller than maxVal.
Therefore, using for-loop would be better.
Attached is a proposed new FloatSplitter.java
{code}
/**
* 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.
*/
// modified by Jongho Lee at Samsung SDS.
package org.apache.sqoop.mapreduce.db;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.InputSplit;
import com.cloudera.sqoop.config.ConfigurationHelper;
import com.cloudera.sqoop.mapreduce.db.DBSplitter;
import com.cloudera.sqoop.mapreduce.db.DataDrivenDBInputFormat;
/**
* Implement DBSplitter over floating-point values.
*/
public class FloatSplitter implements DBSplitter {
private static final Log LOG = LogFactory.getLog(FloatSplitter.class);
private static final double MIN_INCREMENT = 10000 * Double.MIN_VALUE;
public List<InputSplit> split(Configuration conf, ResultSet results,
String colName) throws SQLException {
LOG.warn("Generating splits for a floating-point index column. Due to the");
LOG.warn("imprecise representation of floating-point values in Java, this");
LOG.warn("may result in an incomplete import.");
LOG.warn("You are strongly encouraged to choose an integral split column.");
List<InputSplit> splits = new ArrayList<InputSplit>();
if (results.getString(1) == null && results.getString(2) == null) {
// Range is null to null. Return a null split accordingly.
splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
colName + " IS NULL", colName + " IS NULL"));
return splits;
}
double minVal = results.getDouble(1);
double maxVal = results.getDouble(2);
// Use this as a hint. May need an extra task if the size doesn't
// divide cleanly.
int numSplits = ConfigurationHelper.getConfNumMaps(conf);
double splitSize = (maxVal - minVal) / (double) numSplits;
if (splitSize < MIN_INCREMENT) {
splitSize = MIN_INCREMENT;
}
String lowClausePrefix = colName + " >= ";
String highClausePrefix = colName + " < ";
double curLower = minVal;
double curUpper = curLower + splitSize;
for (int i = 0; i < numSplits - 1; i++) {
// while (curUpper < maxVal) { // changed to for loop
splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
lowClausePrefix + Double.toString(curLower),
highClausePrefix + Double.toString(curUpper)));
curLower = curUpper;
curUpper += splitSize;
}
// Catch any overage and create the closed interval for the last split.
if (curLower <= maxVal || splits.size() == 1) {
splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
lowClausePrefix + Double.toString(curLower),
colName + " <= " + Double.toString(maxVal)));
// curUpper -> curLower // changed
}
if (results.getString(1) == null || results.getString(2) == null) {
// At least one extrema is null; add a null split.
splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
colName + " IS NULL", colName + " IS NULL"));
}
return splits;
}
}
{code}
was:
When we used Sqoop to load data from mySQL using one double column as split-key
in Samsung SDS,
the last mapper did not load data from mySQL at all.
The number of mappers was sometimes increased by 1.
I think they were caused by some bugs in FloatSplitter.java
For the last split, lowClausePrefix + Double.toString(curUpper), may be
lowClausePrefix + Double.toString(curLower).
In while (curUpper < maxVal) loop, because of round-off error,
minVal + splitSize * numSplits can be smaller than maxVal.
Therefore, using for-loop would be better.
Attached is a proposed new FloatSplitter.java
/**
* 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.
*/
// modified by Jongho Lee at Samsung SDS.
package org.apache.sqoop.mapreduce.db;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.InputSplit;
import com.cloudera.sqoop.config.ConfigurationHelper;
import com.cloudera.sqoop.mapreduce.db.DBSplitter;
import com.cloudera.sqoop.mapreduce.db.DataDrivenDBInputFormat;
/**
* Implement DBSplitter over floating-point values.
*/
public class FloatSplitter implements DBSplitter {
private static final Log LOG = LogFactory.getLog(FloatSplitter.class);
private static final double MIN_INCREMENT = 10000 * Double.MIN_VALUE;
public List<InputSplit> split(Configuration conf, ResultSet results,
String colName) throws SQLException {
LOG.warn("Generating splits for a floating-point index column. Due to the");
LOG.warn("imprecise representation of floating-point values in Java, this");
LOG.warn("may result in an incomplete import.");
LOG.warn("You are strongly encouraged to choose an integral split column.");
List<InputSplit> splits = new ArrayList<InputSplit>();
if (results.getString(1) == null && results.getString(2) == null) {
// Range is null to null. Return a null split accordingly.
splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
colName + " IS NULL", colName + " IS NULL"));
return splits;
}
double minVal = results.getDouble(1);
double maxVal = results.getDouble(2);
// Use this as a hint. May need an extra task if the size doesn't
// divide cleanly.
int numSplits = ConfigurationHelper.getConfNumMaps(conf);
double splitSize = (maxVal - minVal) / (double) numSplits;
if (splitSize < MIN_INCREMENT) {
splitSize = MIN_INCREMENT;
}
String lowClausePrefix = colName + " >= ";
String highClausePrefix = colName + " < ";
double curLower = minVal;
double curUpper = curLower + splitSize;
for (int i = 0; i < numSplits - 1; i++) {
// while (curUpper < maxVal) { // changed to for loop
splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
lowClausePrefix + Double.toString(curLower),
highClausePrefix + Double.toString(curUpper)));
curLower = curUpper;
curUpper += splitSize;
}
// Catch any overage and create the closed interval for the last split.
if (curLower <= maxVal || splits.size() == 1) {
splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
lowClausePrefix + Double.toString(curLower),
colName + " <= " + Double.toString(maxVal)));
// curUpper -> curLower // changed
}
if (results.getString(1) == null || results.getString(2) == null) {
// At least one extrema is null; add a null split.
splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
colName + " IS NULL", colName + " IS NULL"));
}
return splits;
}
}
> One mapper does not load data from mySql if double column is used as split key
> ------------------------------------------------------------------------------
>
> Key: SQOOP-1312
> URL: https://issues.apache.org/jira/browse/SQOOP-1312
> Project: Sqoop
> Issue Type: Bug
> Affects Versions: 1.4.4
> Reporter: Jong Ho Lee
>
> When we used Sqoop to load data from mySQL using one double column as
> split-key in Samsung SDS,
> the last mapper did not load data from mySQL at all.
> The number of mappers was sometimes increased by 1.
> I think they were caused by some bugs in FloatSplitter.java
> For the last split, lowClausePrefix + Double.toString(curUpper), may be
> lowClausePrefix + Double.toString(curLower).
> In while (curUpper < maxVal) loop, because of round-off error,
> minVal + splitSize * numSplits can be smaller than maxVal.
> Therefore, using for-loop would be better.
> Attached is a proposed new FloatSplitter.java
> {code}
> /**
> * 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.
> */
> // modified by Jongho Lee at Samsung SDS.
> package org.apache.sqoop.mapreduce.db;
> import java.sql.ResultSet;
> import java.sql.SQLException;
> import java.util.ArrayList;
> import java.util.List;
> import org.apache.commons.logging.Log;
> import org.apache.commons.logging.LogFactory;
> import org.apache.hadoop.conf.Configuration;
> import org.apache.hadoop.mapreduce.InputSplit;
> import com.cloudera.sqoop.config.ConfigurationHelper;
> import com.cloudera.sqoop.mapreduce.db.DBSplitter;
> import com.cloudera.sqoop.mapreduce.db.DataDrivenDBInputFormat;
> /**
> * Implement DBSplitter over floating-point values.
> */
> public class FloatSplitter implements DBSplitter {
> private static final Log LOG = LogFactory.getLog(FloatSplitter.class);
> private static final double MIN_INCREMENT = 10000 * Double.MIN_VALUE;
> public List<InputSplit> split(Configuration conf, ResultSet results,
> String colName) throws SQLException {
> LOG.warn("Generating splits for a floating-point index column. Due to
> the");
> LOG.warn("imprecise representation of floating-point values in Java,
> this");
> LOG.warn("may result in an incomplete import.");
> LOG.warn("You are strongly encouraged to choose an integral split
> column.");
> List<InputSplit> splits = new ArrayList<InputSplit>();
> if (results.getString(1) == null && results.getString(2) == null) {
> // Range is null to null. Return a null split accordingly.
> splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
> colName + " IS NULL", colName + " IS NULL"));
> return splits;
> }
> double minVal = results.getDouble(1);
> double maxVal = results.getDouble(2);
> // Use this as a hint. May need an extra task if the size doesn't
> // divide cleanly.
> int numSplits = ConfigurationHelper.getConfNumMaps(conf);
> double splitSize = (maxVal - minVal) / (double) numSplits;
> if (splitSize < MIN_INCREMENT) {
> splitSize = MIN_INCREMENT;
> }
> String lowClausePrefix = colName + " >= ";
> String highClausePrefix = colName + " < ";
> double curLower = minVal;
> double curUpper = curLower + splitSize;
> for (int i = 0; i < numSplits - 1; i++) {
> // while (curUpper < maxVal) { // changed to for loop
> splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
> lowClausePrefix + Double.toString(curLower),
> highClausePrefix + Double.toString(curUpper)));
> curLower = curUpper;
> curUpper += splitSize;
> }
> // Catch any overage and create the closed interval for the last split.
> if (curLower <= maxVal || splits.size() == 1) {
> splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
> lowClausePrefix + Double.toString(curLower),
> colName + " <= " + Double.toString(maxVal)));
> // curUpper -> curLower // changed
> }
> if (results.getString(1) == null || results.getString(2) == null) {
> // At least one extrema is null; add a null split.
> splits.add(new DataDrivenDBInputFormat.DataDrivenDBInputSplit(
> colName + " IS NULL", colName + " IS NULL"));
> }
> return splits;
> }
> }
> {code}
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