/**
* 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.hbase.mapreduce;
import java.io.IOException;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.util.Base64;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Counter;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.util.StringUtils;
/**
* Emits Sorted KeyValues. Reads the text passed, parses it and creates the Key Values then Sorts
* them and emits Keyalues in sorted order.
* @see HFileOutputFormat
* @see KeyValueSortReducer
* @see PutSortReducer
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class TextSortReducer extends
Reducer<ImmutableBytesWritable, Text, ImmutableBytesWritable, KeyValue> {
/** Timestamp for all inserted rows */
private long ts;
/** Column seperator */
private String separator;
/** Should skip bad lines */
private boolean skipBadLines;
private Counter badLineCount;
private ImportTsv.TsvParser parser;
public long getTs() {
return ts;
}
public boolean getSkipBadLines() {
return skipBadLines;
}
public Counter getBadLineCount() {
return badLineCount;
}
public void incrementBadLineCount(int count) {
this.badLineCount.increment(count);
}
/**
* Handles initializing this class with objects specific to it (i.e., the parser).
* Common initialization that might be leveraged by a subsclass is done in
* <code>doSetup</code>. Hence a subclass may choose to override this method
* and call <code>doSetup</code> as well before handling it's own custom params.
*
* @param context
*/
@Override
protected void setup(Context context) {
doSetup(context);
Configuration conf = context.getConfiguration();
parser = new ImportTsv.TsvParser(conf.get(ImportTsv.COLUMNS_CONF_KEY), separator);
if (parser.getRowKeyColumnIndex() == -1) {
throw new RuntimeException("No row key column specified");
}
}
/**
* Handles common parameter initialization that a subclass might want to leverage.
* @param context
*/
protected void doSetup(Context context) {
Configuration conf = context.getConfiguration();
// If a custom separator has been used,
// decode it back from Base64 encoding.
separator = conf.get(ImportTsv.SEPARATOR_CONF_KEY);
if (separator == null) {
separator = ImportTsv.DEFAULT_SEPARATOR;
} else {
separator = new String(Base64.decode(separator));
}
// Should never get 0 as we are setting this to a valid value in job configuration.
ts = conf.getLong(ImportTsv.TIMESTAMP_CONF_KEY, 0);
skipBadLines = context.getConfiguration().getBoolean(ImportTsv.SKIP_LINES_CONF_KEY, true);
badLineCount = context.getCounter("ImportTsv", "Bad Lines");
}
@Override
protected void reduce(
ImmutableBytesWritable rowKey,
java.lang.Iterable<Text> lines,
Reducer<ImmutableBytesWritable, Text,
ImmutableBytesWritable, KeyValue>.Context context)
throws java.io.IOException, InterruptedException
{
// although reduce() is called per-row, handle pathological case
long threshold = context.getConfiguration().getLong(
"reducer.row.threshold", 1L * (1<<30));
Iterator<Text> iter = lines.iterator();
while (iter.hasNext()) {
Set<KeyValue> kvs = new TreeSet<KeyValue>(KeyValue.COMPARATOR);
long curSize = 0;
// stop at the end or the RAM threshold
while (iter.hasNext() && curSize < threshold) {
Text line = iter.next();
byte[] lineBytes = line.getBytes();
try {
ImportTsv.TsvParser.ParsedLine parsed = parser.parse(lineBytes, line.getLength());
// Retrieve timestamp if exists
ts = parsed.getTimestamp(ts);
for (int i = 0; i < parsed.getColumnCount(); i++) {
if (i == parser.getRowKeyColumnIndex() || i == parser.getTimestampKeyColumnIndex()) {
continue;
}
KeyValue kv = new KeyValue(lineBytes, parsed.getRowKeyOffset(),
parsed.getRowKeyLength(), parser.getFamily(i), 0,
parser.getFamily(i).length, parser.getQualifier(i), 0,
parser.getQualifier(i).length, ts, KeyValue.Type.Put,
lineBytes, parsed.getColumnOffset(i), parsed.getColumnLength(i));
kvs.add(kv);
curSize += kv.heapSize();
}
} catch (ImportTsv.TsvParser.BadTsvLineException badLine) {
if (skipBadLines) {
System.err.println("Bad line." + badLine.getMessage());
incrementBadLineCount(1);
return;
}
throw new IOException(badLine);
} catch (IllegalArgumentException e) {
if (skipBadLines) {
System.err.println("Bad line." + e.getMessage());
incrementBadLineCount(1);
return;
}
throw new IOException(e);
}
}
context.setStatus("Read " + kvs.size() + " entries of " + kvs.getClass()
+ "(" + StringUtils.humanReadableInt(curSize) + ")");
int index = 0;
for (KeyValue kv : kvs) {
context.write(rowKey, kv);
if (++index > 0 && index % 100 == 0)
context.setStatus("Wrote " + index + " key values.");
}
// if we have more entries to process
if (iter.hasNext()) {
// force flush because we cannot guarantee intra-row sorted order
context.write(null, null);
}
}
}
}