org.apache.hadoop.hbase.mapreduce.TableInputFormatBase Maven / Gradle / Ivy
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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.hbase.mapreduce;
import java.io.Closeable;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import javax.naming.NamingException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.RegionLocator;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.util.Addressing;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.Pair;
import org.apache.hadoop.hbase.util.RegionSizeCalculator;
import org.apache.hadoop.hbase.util.Strings;
import org.apache.hadoop.mapreduce.InputFormat;
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.net.DNS;
import org.apache.hadoop.util.StringUtils;
/**
* A base for {@link TableInputFormat}s. Receives a {@link Connection}, a {@link TableName},
* an {@link Scan} instance that defines the input columns etc. Subclasses may use
* other TableRecordReader implementations.
*
* An example of a subclass:
*
* class ExampleTIF extends TableInputFormatBase implements JobConfigurable {
*
* public void configure(JobConf job) {
* Connection connection =
* ConnectionFactory.createConnection(HBaseConfiguration.create(job));
* TableName tableName = TableName.valueOf("exampleTable");
* // mandatory
* initializeTable(connection, tableName);
* Text[] inputColumns = new byte [][] { Bytes.toBytes("cf1:columnA"),
* Bytes.toBytes("cf2") };
* // mandatory
* setInputColumns(inputColumns);
* RowFilterInterface exampleFilter = new RegExpRowFilter("keyPrefix.*");
* // optional
* setRowFilter(exampleFilter);
* }
*
* public void validateInput(JobConf job) throws IOException {
* }
* }
*
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class TableInputFormatBase
extends InputFormat {
final Log LOG = LogFactory.getLog(TableInputFormatBase.class);
/** Holds the details for the internal scanner.
*
* @see Scan */
private Scan scan = null;
/** The {@link Admin}. */
private Admin admin;
/** The {@link Table} to scan. */
private Table table;
/** The {@link RegionLocator} of the table. */
private RegionLocator regionLocator;
/** The reader scanning the table, can be a custom one. */
private TableRecordReader tableRecordReader = null;
/** The reverse DNS lookup cache mapping: IPAddress => HostName */
private HashMap reverseDNSCacheMap =
new HashMap();
private Connection connection;
/**
* Builds a {@link TableRecordReader}. If no {@link TableRecordReader} was provided, uses
* the default.
*
* @param split The split to work with.
* @param context The current context.
* @return The newly created record reader.
* @throws IOException When creating the reader fails.
* @see org.apache.hadoop.mapreduce.InputFormat#createRecordReader(
* org.apache.hadoop.mapreduce.InputSplit,
* org.apache.hadoop.mapreduce.TaskAttemptContext)
*/
@Override
public RecordReader createRecordReader(
InputSplit split, TaskAttemptContext context)
throws IOException {
if (table == null) {
throw new IOException("Cannot create a record reader because of a" +
" previous error. Please look at the previous logs lines from" +
" the task's full log for more details.");
}
TableSplit tSplit = (TableSplit) split;
LOG.info("Input split length: " + StringUtils.humanReadableInt(tSplit.getLength()) + " bytes.");
final TableRecordReader trr =
this.tableRecordReader != null ? this.tableRecordReader : new TableRecordReader();
Scan sc = new Scan(this.scan);
sc.setStartRow(tSplit.getStartRow());
sc.setStopRow(tSplit.getEndRow());
trr.setScan(sc);
trr.setTable(table);
return new RecordReader() {
@Override
public void close() throws IOException {
trr.close();
close(admin, table, regionLocator, connection);
}
private void close(Closeable... closables) throws IOException {
for (Closeable c : closables) {
if(c != null) { c.close(); }
}
}
@Override
public ImmutableBytesWritable getCurrentKey() throws IOException, InterruptedException {
return trr.getCurrentKey();
}
@Override
public Result getCurrentValue() throws IOException, InterruptedException {
return trr.getCurrentValue();
}
@Override
public float getProgress() throws IOException, InterruptedException {
return trr.getProgress();
}
@Override
public void initialize(InputSplit inputsplit, TaskAttemptContext context) throws IOException,
InterruptedException {
trr.initialize(inputsplit, context);
}
@Override
public boolean nextKeyValue() throws IOException, InterruptedException {
return trr.nextKeyValue();
}
};
}
protected Pair getStartEndKeys() throws IOException {
return regionLocator.getStartEndKeys();
}
/**
* Calculates the splits that will serve as input for the map tasks. The
* number of splits matches the number of regions in a table.
*
* @param context The current job context.
* @return The list of input splits.
* @throws IOException When creating the list of splits fails.
* @see org.apache.hadoop.mapreduce.InputFormat#getSplits(
* org.apache.hadoop.mapreduce.JobContext)
*/
@Override
public List getSplits(JobContext context) throws IOException {
if (table == null) {
throw new IOException("No table was provided.");
}
RegionSizeCalculator sizeCalculator = new RegionSizeCalculator(regionLocator, admin);
Pair keys = getStartEndKeys();
if (keys == null || keys.getFirst() == null ||
keys.getFirst().length == 0) {
HRegionLocation regLoc = regionLocator.getRegionLocation(HConstants.EMPTY_BYTE_ARRAY, false);
if (null == regLoc) {
throw new IOException("Expecting at least one region.");
}
List splits = new ArrayList(1);
long regionSize = sizeCalculator.getRegionSize(regLoc.getRegionInfo().getRegionName());
TableSplit split = new TableSplit(table.getName(),
HConstants.EMPTY_BYTE_ARRAY, HConstants.EMPTY_BYTE_ARRAY, regLoc
.getHostnamePort().split(Addressing.HOSTNAME_PORT_SEPARATOR)[0], regionSize);
splits.add(split);
return splits;
}
List splits = new ArrayList(keys.getFirst().length);
for (int i = 0; i < keys.getFirst().length; i++) {
if ( !includeRegionInSplit(keys.getFirst()[i], keys.getSecond()[i])) {
continue;
}
HRegionLocation location = regionLocator.getRegionLocation(keys.getFirst()[i], false);
// The below InetSocketAddress creation does a name resolution.
InetSocketAddress isa = new InetSocketAddress(location.getHostname(), location.getPort());
if (isa.isUnresolved()) {
LOG.warn("Failed resolve " + isa);
}
InetAddress regionAddress = isa.getAddress();
String regionLocation;
try {
regionLocation = reverseDNS(regionAddress);
} catch (NamingException e) {
LOG.warn("Cannot resolve the host name for " + regionAddress + " because of " + e);
regionLocation = location.getHostname();
}
byte[] startRow = scan.getStartRow();
byte[] stopRow = scan.getStopRow();
// determine if the given start an stop key fall into the region
if ((startRow.length == 0 || keys.getSecond()[i].length == 0 ||
Bytes.compareTo(startRow, keys.getSecond()[i]) < 0) &&
(stopRow.length == 0 ||
Bytes.compareTo(stopRow, keys.getFirst()[i]) > 0)) {
byte[] splitStart = startRow.length == 0 ||
Bytes.compareTo(keys.getFirst()[i], startRow) >= 0 ?
keys.getFirst()[i] : startRow;
byte[] splitStop = (stopRow.length == 0 ||
Bytes.compareTo(keys.getSecond()[i], stopRow) <= 0) &&
keys.getSecond()[i].length > 0 ?
keys.getSecond()[i] : stopRow;
byte[] regionName = location.getRegionInfo().getRegionName();
long regionSize = sizeCalculator.getRegionSize(regionName);
TableSplit split = new TableSplit(table.getName(),
splitStart, splitStop, regionLocation, regionSize);
splits.add(split);
if (LOG.isDebugEnabled()) {
LOG.debug("getSplits: split -> " + i + " -> " + split);
}
}
}
return splits;
}
public String reverseDNS(InetAddress ipAddress) throws NamingException, UnknownHostException {
String hostName = this.reverseDNSCacheMap.get(ipAddress);
if (hostName == null) {
String ipAddressString = null;
try {
ipAddressString = DNS.reverseDns(ipAddress, null);
} catch (Exception e) {
// We can use InetAddress in case the jndi failed to pull up the reverse DNS entry from the
// name service. Also, in case of ipv6, we need to use the InetAddress since resolving
// reverse DNS using jndi doesn't work well with ipv6 addresses.
ipAddressString = InetAddress.getByName(ipAddress.getHostAddress()).getHostName();
}
if (ipAddressString == null) throw new UnknownHostException("No host found for " + ipAddress);
hostName = Strings.domainNamePointerToHostName(ipAddressString);
this.reverseDNSCacheMap.put(ipAddress, hostName);
}
return hostName;
}
/**
*
*
* Test if the given region is to be included in the InputSplit while splitting
* the regions of a table.
*
* This optimization is effective when there is a specific reasoning to exclude an entire region from the M-R job,
* (and hence, not contributing to the InputSplit), given the start and end keys of the same.
* Useful when we need to remember the last-processed top record and revisit the [last, current) interval for M-R processing,
* continuously. In addition to reducing InputSplits, reduces the load on the region server as well, due to the ordering of the keys.
*
*
* Note: It is possible that endKey.length() == 0 , for the last (recent) region.
*
* Override this method, if you want to bulk exclude regions altogether from M-R. By default, no region is excluded( i.e. all regions are included).
*
*
* @param startKey Start key of the region
* @param endKey End key of the region
* @return true, if this region needs to be included as part of the input (default).
*
*/
protected boolean includeRegionInSplit(final byte[] startKey, final byte [] endKey) {
return true;
}
/**
* Allows subclasses to get the {@link HTable}.
*
* @deprecated
*/
@Deprecated
protected HTable getHTable() {
return (HTable) this.table;
}
/**
* Allows subclasses to get the {@link RegionLocator}.
*/
protected RegionLocator getRegionLocator() {
return regionLocator;
}
/**
* Allows subclasses to get the {@link Table}.
*/
protected Table getTable() {
return table;
}
/**
* Allows subclasses to get the {@link Admin}.
*/
protected Admin getAdmin() {
return admin;
}
/**
* Allows subclasses to set the {@link HTable}.
*
* @param table The table to get the data from.
* @throws IOException
* @deprecated Use {@link #initializeTable(Connection, TableName)} instead.
*/
@Deprecated
protected void setHTable(HTable table) throws IOException {
this.table = table;
this.regionLocator = table;
this.admin = table.getConnection().getAdmin();
}
/**
* Allows subclasses to initialize the table information.
*
* @param connection The {@link Connection} to the HBase cluster.
* @param tableName The {@link TableName} of the table to process.
* @throws IOException
*/
protected void initializeTable(Connection connection, TableName tableName) throws IOException {
this.table = connection.getTable(tableName);
this.regionLocator = connection.getRegionLocator(tableName);
this.admin = connection.getAdmin();
this.connection = connection;
}
/**
* Gets the scan defining the actual details like columns etc.
*
* @return The internal scan instance.
*/
public Scan getScan() {
if (this.scan == null) this.scan = new Scan();
return scan;
}
/**
* Sets the scan defining the actual details like columns etc.
*
* @param scan The scan to set.
*/
public void setScan(Scan scan) {
this.scan = scan;
}
/**
* Allows subclasses to set the {@link TableRecordReader}.
*
* @param tableRecordReader A different {@link TableRecordReader}
* implementation.
*/
protected void setTableRecordReader(TableRecordReader tableRecordReader) {
this.tableRecordReader = tableRecordReader;
}
}