org.apache.hadoop.hbase.mapreduce.TableInputFormatBase Maven / Gradle / Ivy
Show all versions of hbase-server Show documentation
/**
*
* 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.Arrays;
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.conf.Configuration;
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.ConnectionFactory;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.NeedUnmanagedConnectionException;
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.
*
* Subclasses MUST ensure initializeTable(Connection, TableName) is called for an instance to
* function properly. Each of the entry points to this class used by the MapReduce framework,
* {@link #createRecordReader(InputSplit, TaskAttemptContext)} and {@link #getSplits(JobContext)},
* will call {@link #initialize(JobContext)} as a convenient centralized location to handle
* retrieving the necessary configuration information. If your subclass overrides either of these
* methods, either call the parent version or call initialize yourself.
*
*
* An example of a subclass:
*
* class ExampleTIF extends TableInputFormatBase {
*
* {@literal @}Override
* protected void initialize(JobContext context) throws IOException {
* // We are responsible for the lifecycle of this connection until we hand it over in
* // initializeTable.
* Connection connection = ConnectionFactory.createConnection(HBaseConfiguration.create(
* job.getConfiguration()));
* TableName tableName = TableName.valueOf("exampleTable");
* // mandatory. once passed here, TableInputFormatBase will handle closing the connection.
* initializeTable(connection, tableName);
* byte[][] inputColumns = new byte [][] { Bytes.toBytes("columnA"),
* Bytes.toBytes("columnB") };
* // optional, by default we'll get everything for the table.
* Scan scan = new Scan();
* for (byte[] family : inputColumns) {
* scan.addFamily(family);
* }
* Filter exampleFilter = new RowFilter(CompareOp.EQUAL, new RegexStringComparator("aa.*"));
* scan.setFilter(exampleFilter);
* setScan(scan);
* }
* }
*
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class TableInputFormatBase
extends InputFormat {
/** Specify if we enable auto-balance for input in M/R jobs.*/
public static final String MAPREDUCE_INPUT_AUTOBALANCE = "hbase.mapreduce.input.autobalance";
/** Specify if ratio for data skew in M/R jobs, it goes well with the enabling hbase.mapreduce
* .input.autobalance property.*/
public static final String INPUT_AUTOBALANCE_MAXSKEWRATIO = "hbase.mapreduce.input.autobalance" +
".maxskewratio";
/** Specify if the row key in table is text (ASCII between 32~126),
* default is true. False means the table is using binary row key*/
public static final String TABLE_ROW_TEXTKEY = "hbase.table.row.textkey";
private static final Log LOG = LogFactory.getLog(TableInputFormatBase.class);
private static final String NOT_INITIALIZED = "The input format instance has not been properly " +
"initialized. Ensure you call initializeTable either in your constructor or initialize " +
"method";
private static final String INITIALIZATION_ERROR = "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.";
/** 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 underlying {@link Connection} of the table. */
private Connection connection;
/** The reverse DNS lookup cache mapping: IPAddress => HostName */
private HashMap reverseDNSCacheMap =
new HashMap();
/**
* 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 {
// Just in case a subclass is relying on JobConfigurable magic.
if (table == null) {
initialize(context);
}
// null check in case our child overrides getTable to not throw.
try {
if (getTable() == null) {
// initialize() must not have been implemented in the subclass.
throw new IOException(INITIALIZATION_ERROR);
}
} catch (IllegalStateException exception) {
throw new IOException(INITIALIZATION_ERROR, exception);
}
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(getTable());
return new RecordReader() {
@Override
public void close() throws IOException {
trr.close();
closeTable();
}
@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 getRegionLocator().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 {
boolean closeOnFinish = false;
// Just in case a subclass is relying on JobConfigurable magic.
if (table == null) {
initialize(context);
closeOnFinish = true;
}
// null check in case our child overrides getTable to not throw.
try {
if (getTable() == null) {
// initialize() must not have been implemented in the subclass.
throw new IOException(INITIALIZATION_ERROR);
}
} catch (IllegalStateException exception) {
throw new IOException(INITIALIZATION_ERROR, exception);
}
try {
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(), scan,
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();
String encodedRegionName = location.getRegionInfo().getEncodedName();
long regionSize = sizeCalculator.getRegionSize(regionName);
TableSplit split = new TableSplit(table.getName(), scan,
splitStart, splitStop, regionLocation, encodedRegionName, regionSize);
splits.add(split);
if (LOG.isDebugEnabled()) {
LOG.debug("getSplits: split -> " + i + " -> " + split);
}
}
}
//The default value of "hbase.mapreduce.input.autobalance" is false, which means not enabled.
boolean enableAutoBalance = context.getConfiguration().getBoolean(
MAPREDUCE_INPUT_AUTOBALANCE, false);
if (enableAutoBalance) {
long totalRegionSize=0;
for (int i = 0; i < splits.size(); i++){
TableSplit ts = (TableSplit)splits.get(i);
totalRegionSize += ts.getLength();
}
long averageRegionSize = totalRegionSize / splits.size();
// the averageRegionSize must be positive.
if (averageRegionSize <= 0) {
LOG.warn("The averageRegionSize is not positive: "+ averageRegionSize + ", " +
"set it to 1.");
averageRegionSize = 1;
}
return calculateRebalancedSplits(splits, context, averageRegionSize);
} else {
return splits;
}
} finally {
if (closeOnFinish) {
closeTable();
}
}
}
/**
* @deprecated mistakenly made public in 0.98.7. scope will change to package-private
*/
@Deprecated
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;
}
/**
* Calculates the number of MapReduce input splits for the map tasks. The number of
* MapReduce input splits depends on the average region size and the "data skew ratio" user set in
* configuration.
*
* @param list The list of input splits before balance.
* @param context The current job context.
* @param average The average size of all regions .
* @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)
*/
public List calculateRebalancedSplits(List list, JobContext context,
long average) throws IOException {
List resultList = new ArrayList();
Configuration conf = context.getConfiguration();
//The default data skew ratio is 3
long dataSkewRatio = conf.getLong(INPUT_AUTOBALANCE_MAXSKEWRATIO, 3);
//It determines which mode to use: text key mode or binary key mode. The default is text mode.
boolean isTextKey = context.getConfiguration().getBoolean(TABLE_ROW_TEXTKEY, true);
long dataSkewThreshold = dataSkewRatio * average;
int count = 0;
while (count < list.size()) {
TableSplit ts = (TableSplit)list.get(count);
TableName tableName = ts.getTable();
String regionLocation = ts.getRegionLocation();
String encodedRegionName = ts.getEncodedRegionName();
long regionSize = ts.getLength();
if (regionSize >= dataSkewThreshold) {
// if the current region size is large than the data skew threshold,
// split the region into two MapReduce input splits.
byte[] splitKey = getSplitKey(ts.getStartRow(), ts.getEndRow(), isTextKey);
if (Arrays.equals(ts.getEndRow(), splitKey)) {
// Not splitting since the end key is the same as the split key
resultList.add(ts);
} else {
//Set the size of child TableSplit as 1/2 of the region size. The exact size of the
// MapReduce input splits is not far off.
TableSplit t1 = new TableSplit(tableName, scan, ts.getStartRow(), splitKey,
regionLocation, regionSize / 2);
TableSplit t2 = new TableSplit(tableName, scan, splitKey, ts.getEndRow(), regionLocation,
regionSize - regionSize / 2);
resultList.add(t1);
resultList.add(t2);
}
count++;
} else if (regionSize >= average) {
// if the region size between average size and data skew threshold size,
// make this region as one MapReduce input split.
resultList.add(ts);
count++;
} else {
// if the total size of several small continuous regions less than the average region size,
// combine them into one MapReduce input split.
long totalSize = regionSize;
byte[] splitStartKey = ts.getStartRow();
byte[] splitEndKey = ts.getEndRow();
count++;
for (; count < list.size(); count++) {
TableSplit nextRegion = (TableSplit)list.get(count);
long nextRegionSize = nextRegion.getLength();
if (totalSize + nextRegionSize <= dataSkewThreshold) {
totalSize = totalSize + nextRegionSize;
splitEndKey = nextRegion.getEndRow();
} else {
break;
}
}
TableSplit t = new TableSplit(table.getName(), scan, splitStartKey, splitEndKey,
regionLocation, encodedRegionName, totalSize);
resultList.add(t);
}
}
return resultList;
}
/**
* select a split point in the region. The selection of the split point is based on an uniform
* distribution assumption for the keys in a region.
* Here are some examples:
*
*
*
* start key
* end key
* is text
* split point
*
*
* 'a', 'a', 'a', 'b', 'c', 'd', 'e', 'f', 'g'
* 'a', 'a', 'a', 'f', 'f', 'f'
* true
* 'a', 'a', 'a', 'd', 'd', -78, 50, -77, 51
*
*
* '1', '1', '1', '0', '0', '0'
* '1', '1', '2', '5', '7', '9', '0'
* true
* '1', '1', '1', -78, -77, -76, -104
*
*
* '1', '1', '1', '0'
* '1', '1', '2', '0'
* true
* '1', '1', '1', -80
*
*
* 13, -19, 126, 127
* 13, -19, 127, 0
* false
* 13, -19, 126, -65
*
*
*
* Set this function as "public static", make it easier for test.
*
* @param start Start key of the region
* @param end End key of the region
* @param isText It determines to use text key mode or binary key mode
* @return The split point in the region.
*/
public static byte[] getSplitKey(byte[] start, byte[] end, boolean isText) {
byte upperLimitByte;
byte lowerLimitByte;
//Use text mode or binary mode.
if (isText) {
//The range of text char set in ASCII is [32,126], the lower limit is space and the upper
// limit is '~'.
upperLimitByte = '~';
lowerLimitByte = ' ';
} else {
upperLimitByte = -1;
lowerLimitByte = 0;
}
// For special case
// Example 1 : startkey=null, endkey="hhhqqqwww", splitKey="h"
// Example 2 (text key mode): startKey="ffffaaa", endKey=null, splitkey="f~~~~~~"
if (start.length == 0 && end.length == 0){
return new byte[]{(byte) ((lowerLimitByte + upperLimitByte) / 2)};
}
if (start.length == 0 && end.length != 0){
return new byte[]{ end[0] };
}
if (start.length != 0 && end.length == 0){
byte[] result =new byte[start.length];
result[0]=start[0];
for (int k = 1; k < start.length; k++){
result[k] = upperLimitByte;
}
return result;
}
return Bytes.split(start, end, false, 1)[1];
}
/**
*
*
* 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 use {@link #getTable()}
*/
@Deprecated
protected HTable getHTable() {
return (HTable) this.getTable();
}
/**
* Allows subclasses to get the {@link RegionLocator}.
*/
protected RegionLocator getRegionLocator() {
if (regionLocator == null) {
throw new IllegalStateException(NOT_INITIALIZED);
}
return regionLocator;
}
/**
* Allows subclasses to get the {@link Table}.
*/
protected Table getTable() {
if (table == null) {
throw new IllegalStateException(NOT_INITIALIZED);
}
return table;
}
/**
* Allows subclasses to get the {@link Admin}.
*/
protected Admin getAdmin() {
if (admin == null) {
throw new IllegalStateException(NOT_INITIALIZED);
}
return admin;
}
/**
* Allows subclasses to set the {@link HTable}.
*
* Will attempt to reuse the underlying Connection for our own needs, including
* retreiving an Admin interface to the HBase cluster.
*
* @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.connection = table.getConnection();
try {
this.regionLocator = table.getRegionLocator();
this.admin = this.connection.getAdmin();
} catch (NeedUnmanagedConnectionException exception) {
LOG.warn("You are using an HTable instance that relies on an HBase-managed Connection. " +
"This is usually due to directly creating an HTable, which is deprecated. Instead, you " +
"should create a Connection object and then request a Table instance from it. If you " +
"don't need the Table instance for your own use, you should instead use the " +
"TableInputFormatBase.initalizeTable method directly.");
LOG.info("Creating an additional unmanaged connection because user provided one can't be " +
"used for administrative actions. We'll close it when we close out the table.");
LOG.debug("Details about our failure to request an administrative interface.", exception);
// Do we need a "copy the settings from this Connection" method? are things like the User
// properly maintained by just looking again at the Configuration?
this.connection = ConnectionFactory.createConnection(this.connection.getConfiguration());
this.regionLocator = this.connection.getRegionLocator(table.getName());
this.admin = this.connection.getAdmin();
}
}
/**
* Allows subclasses to initialize the table information.
*
* @param connection The {@link Connection} to the HBase cluster. MUST be unmanaged. We will close.
* @param tableName The {@link TableName} of the table to process.
* @throws IOException
*/
protected void initializeTable(Connection connection, TableName tableName) throws IOException {
if (this.table != null || this.connection != null) {
LOG.warn("initializeTable called multiple times. Overwriting connection and table " +
"reference; TableInputFormatBase will not close these old references when done.");
}
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;
}
/**
* Handle subclass specific set up.
* Each of the entry points used by the MapReduce framework,
* {@link #createRecordReader(InputSplit, TaskAttemptContext)} and {@link #getSplits(JobContext)},
* will call {@link #initialize(JobContext)} as a convenient centralized location to handle
* retrieving the necessary configuration information and calling
* {@link #initializeTable(Connection, TableName)}.
*
* Subclasses should implement their initialize call such that it is safe to call multiple times.
* The current TableInputFormatBase implementation relies on a non-null table reference to decide
* if an initialize call is needed, but this behavior may change in the future. In particular,
* it is critical that initializeTable not be called multiple times since this will leak
* Connection instances.
*
*/
protected void initialize(JobContext context) throws IOException {
}
/**
* Close the Table and related objects that were initialized via
* {@link #initializeTable(Connection, TableName)}.
*
* @throws IOException
*/
protected void closeTable() throws IOException {
close(admin, table, regionLocator, connection);
admin = null;
table = null;
regionLocator = null;
connection = null;
}
private void close(Closeable... closables) throws IOException {
for (Closeable c : closables) {
if(c != null) { c.close(); }
}
}
}