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HBASE-3448 : RegionSplitter, utility class to manually split tables 

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1061637 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Nicolas Spiegelberg 2011-01-21 05:17:32 +00:00
parent 81d751f9d0
commit fb52f98a01
2 changed files with 753 additions and 1 deletions
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10
src/main/java/org/apache/hadoop/hbase/client/HTable.java
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@ -19,9 +19,9 @@
*/
package org.apache.hadoop.hbase.client;
import java.io.IOException;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.Arrays;
@ -1330,6 +1330,14 @@ public class HTable implements HTableInterface {
getRegionCachePrefetch(tableName);
}
/**
* Explicitly clears the region cache to fetch the latest value from META.
* This is a power user function: avoid unless you know the ramifications.
*/
public void clearRegionCache() {
this.connection.clearRegionCache();
}
@Override
public <T extends CoprocessorProtocol> T coprocessorProxy(
Class<T> protocol, byte[] row) {

744
src/main/java/org/apache/hadoop/hbase/util/RegionSplitter.java Normal file
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@ -0,0 +1,744 @@
/**
* Copyright 2010 The Apache Software Foundation
*
* 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.util;
import java.io.IOException;
import java.math.BigInteger;
import java.util.LinkedList;
import java.util.Set;
import java.util.TreeMap;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.GnuParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.OptionBuilder;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.HServerAddress;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.regionserver.Store;
import org.apache.hadoop.hbase.regionserver.StoreFile;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
/**
* The {@link RegionSplitter} class provides several utilities to help in the
* administration lifecycle for developers who choose to manually split regions
* instead of having HBase handle that automatically. The most useful utilities
* are:
* <p>
* <ul>
* <li>Create a table with a specified number of pre-split regions
* <li>Execute a rolling split of all regions on an existing table
* </ul>
* <p>
* Both operations can be safely done on a live server.
* <p>
* <b>Question:</b> How do I turn off automatic splitting? <br>
* <b>Answer:</b> Automatic splitting is determined by the configuration value
* <i>"hbase.hregion.max.filesize"</i>. It is not recommended that you set this
* to Long.MAX_VALUE in case you forget about manual splits. A suggested setting
* is 100GB, which would result in > 1hr major compactions if reached.
* <p>
* <b>Question:</b> Why did the original authors decide to manually split? <br>
* <b>Answer:</b> Specific workload characteristics of our use case allowed us
* to benefit from a manual split system.
* <p>
* <ul>
* <li>Data (~1k) that would grow instead of being replaced
* <li>Data growth was roughly uniform across all regions
* <li>OLTP workload. Data loss is a big deal.
* </ul>
* <p>
* <b>Question:</b> Why is manual splitting good for this workload? <br>
* <b>Answer:</b> Although automated splitting is not a bad option, there are
* benefits to manual splitting.
* <p>
* <ul>
* <li>With growing amounts of data, splits will continually be needed. Since
* you always know exactly what regions you have, long-term debugging and
* profiling is much easier with manual splits. It is hard to trace the logs to
* understand region level problems if it keeps splitting and getting renamed.
* <li>Data offlining bugs + unknown number of split regions == oh crap! If an
* HLog or StoreFile was mistakenly unprocessed by HBase due to a weird bug and
* you notice it a day or so later, you can be assured that the regions
* specified in these files are the same as the current regions and you have
* less headaches trying to restore/replay your data.
* <li>You can finely tune your compaction algorithm. With roughly uniform data
* growth, it's easy to cause split / compaction storms as the regions all
* roughly hit the same data size at the same time. With manual splits, you can
* let staggered, time-based major compactions spread out your network IO load.
* </ul>
* <p>
* <b>Question:</b> What's the optimal number of pre-split regions to create? <br>
* <b>Answer:</b> Mileage will vary depending upon your application.
* <p>
* The short answer for our application is that we started with 10 pre-split
* regions / server and watched our data growth over time. It's better to err on
* the side of too little regions and rolling split later.
* <p>
* The more complicated answer is that this depends upon the largest storefile
* in your region. With a growing data size, this will get larger over time. You
* want the largest region to be just big enough that the {@link Store} compact
* selection algorithm only compacts it due to a timed major. If you don't, your
* cluster can be prone to compaction storms as the algorithm decides to run
* major compactions on a large series of regions all at once. Note that
* compaction storms are due to the uniform data growth, not the manual split
* decision.
* <p>
* If you pre-split your regions too thin, you can increase the major compaction
* interval by configuring HConstants.MAJOR_COMPACTION_PERIOD. If your data size
* grows too large, use this script to perform a network IO safe rolling split
* of all regions.
*/
public class RegionSplitter {
static final Log LOG = LogFactory.getLog(RegionSplitter.class);
/**
* A generic interface for the RegionSplitter code to use for all it's
* functionality. Note that the original authors of this code use
* {@link MD5StringSplit} to partition their table and set it as default, but
* provided this for your custom algorithm. To use, create a new derived class
* from this interface and call the RegionSplitter class with the argument: <br>
* <b>-D split.algorithm=<your_class_path></b>
*/
public static interface SplitAlgorithm {
/**
* Split a pre-existing region into 2 regions.
*
* @param start
* row
* @param end
* row
* @return the split row to use
*/
byte[] split(byte[] start, byte[] end);
/**
* Split an entire table.
*
* @param numberOfSplits
* number of regions to split the table into
*
* @return array of split keys for the initial regions of the table
*/
byte[][] split(int numberOfSplits);
/**
* In HBase, the first row is represented by an empty byte array. This might
* cause problems with your split algorithm or row printing. All your APIs
* will be passed firstRow() instead of empty array.
*
* @return your representation of your first row
*/
byte[] firstRow();
/**
* In HBase, the last row is represented by an empty byte array. This might
* cause problems with your split algorithm or row printing. All your APIs
* will be passed firstRow() instead of empty array.
*
* @return your representation of your last row
*/
byte[] lastRow();
/**
* @param input
* user or file input for row
* @return byte array representation of this row for HBase
*/
byte[] strToRow(String input);
/**
* @param row
* byte array representing a row in HBase
* @return String to use for debug & file printing
*/
String rowToStr(byte[] row);
/**
* @return the separator character to use when storing / printing the row
*/
String separator();
}
/**
* The main function for the RegionSplitter application. Common uses:
* <p>
* <ul>
* <li>create a table named 'myTable' with 60 pre-split regions containing 2
* column families 'test' & 'rs' bin/hbase
* <ul>
* <li>org.apache.hadoop.hbase.util.RegionSplitter -c 60 -f test:rs myTable
* </ul>
* <li>perform a rolling split of 'myTable' (i.e. 60 => 120 regions), # 2
* outstanding splits at a time bin/hbase
* <ul>
* <li>org.apache.hadoop.hbase.util.RegionSplitter -r -o 2 myTable
* </ul>
* </ul>
*
* @param args
* Usage: RegionSplitter &lt;TABLE&gt; &lt;-c &lt;# regions&gt; -f
* &lt;family:family:...&gt; | -r [-o &lt;# outstanding
* splits&gt;]&gt; [-D &lt;conf.param=value&gt;]
* @throws IOException
* HBase IO problem
* @throws InterruptedException
* user requested exit
* @throws ParseException
* problem parsing user input
*/
@SuppressWarnings("static-access")
public static void main(String[] args) throws IOException,
InterruptedException, ParseException {
Configuration conf = HBaseConfiguration.create();
// parse user input
Options opt = new Options();
opt.addOption(OptionBuilder.withArgName("property=value").hasArg()
.withDescription("Override HBase Configuration Settings").create("D"));
opt.addOption(OptionBuilder.withArgName("region count").hasArg()
.withDescription(
"Create a new table with a pre-split number of regions")
.create("c"));
opt.addOption(OptionBuilder.withArgName("family:family:...").hasArg()
.withDescription(
"Column Families to create with new table. Required with -c")
.create("f"));
opt.addOption("h", false, "Print this usage help");
opt.addOption("r", false, "Perform a rolling split of an existing region");
opt.addOption(OptionBuilder.withArgName("count").hasArg().withDescription(
"Max outstanding splits that have unfinished major compactions")
.create("o"));
opt.addOption(null, "risky", false,
"Skip verification steps to complete quickly."
+ "STRONGLY DISCOURAGED for production systems. ");
CommandLine cmd = new GnuParser().parse(opt, args);
if (cmd.hasOption("D")) {
for (String confOpt : cmd.getOptionValues("D")) {
String[] kv = confOpt.split("=", 2);
if (kv.length == 2) {
conf.set(kv[0], kv[1]);
LOG.debug("-D configuration override: " + kv[0] + "=" + kv[1]);
} else {
throw new ParseException("-D option format invalid: " + confOpt);
}
}
}
if (cmd.hasOption("risky")) {
conf.setBoolean("split.verify", false);
}
boolean createTable = cmd.hasOption("c") && cmd.hasOption("f");
boolean rollingSplit = cmd.hasOption("r");
boolean oneOperOnly = createTable ^ rollingSplit;
if (1 != cmd.getArgList().size() || !oneOperOnly || cmd.hasOption("h")) {
new HelpFormatter().printHelp("RegionSplitter <TABLE>", opt);
return;
}
String tableName = cmd.getArgs()[0];
if (createTable) {
conf.set("split.count", cmd.getOptionValue("c"));
createPresplitTable(tableName, cmd.getOptionValue("f").split(":"), conf);
}
if (rollingSplit) {
if (cmd.hasOption("o")) {
conf.set("split.outstanding", cmd.getOptionValue("o"));
}
rollingSplit(tableName, conf);
}
}
static void createPresplitTable(String tableName, String[] columnFamilies,
Configuration conf) throws IOException, InterruptedException {
Class<? extends SplitAlgorithm> splitClass = conf.getClass(
"split.algorithm", MD5StringSplit.class, SplitAlgorithm.class);
SplitAlgorithm splitAlgo;
try {
splitAlgo = splitClass.newInstance();
} catch (Exception e) {
throw new IOException("Problem loading split algorithm: ", e);
}
final int splitCount = conf.getInt("split.count", 0);
Preconditions.checkArgument(splitCount > 1, "Split count must be > 1");
Preconditions.checkArgument(columnFamilies.length > 0,
"Must specify at least one column family. ");
LOG.debug("Creating table " + tableName + " with " + columnFamilies.length
+ " column families. Presplitting to " + splitCount + " regions");
HTableDescriptor desc = new HTableDescriptor(tableName);
for (String cf : columnFamilies) {
desc.addFamily(new HColumnDescriptor(Bytes.toBytes(cf)));
}
HBaseAdmin admin = new HBaseAdmin(conf);
Preconditions.checkArgument(!admin.tableExists(tableName),
"Table already exists: " + tableName);
admin.createTable(desc, splitAlgo.split(splitCount));
LOG.debug("Table created! Waiting for regions to show online in META...");
if (!conf.getBoolean("split.verify", true)) {
// NOTE: createTable is synchronous on the table, but not on the regions
HTable table = new HTable(tableName);
int onlineRegions = 0;
while (onlineRegions < splitCount) {
onlineRegions = table.getRegionsInfo().size();
LOG.debug(onlineRegions + " of " + splitCount + " regions online...");
if (onlineRegions < splitCount) {
Thread.sleep(10 * 1000); // sleep
}
}
}
LOG.debug("Finished creating table with " + splitCount + " regions");
}
static void rollingSplit(String tableName, Configuration conf)
throws IOException, InterruptedException {
Class<? extends SplitAlgorithm> splitClass = conf.getClass(
"split.algorithm", MD5StringSplit.class, SplitAlgorithm.class);
SplitAlgorithm splitAlgo;
try {
splitAlgo = splitClass.newInstance();
} catch (Exception e) {
throw new IOException("Problem loading split algorithm: ", e);
}
final int minOS = conf.getInt("split.outstanding", 2);
HTable table = new HTable(conf, tableName);
// max outstanding splits. default == 50% of servers
final int MAX_OUTSTANDING = Math.max(table.getCurrentNrHRS() / 2, minOS);
Path hbDir = new Path(conf.get(HConstants.HBASE_DIR));
Path tableDir = HTableDescriptor.getTableDir(hbDir, table.getTableName());
Path splitFile = new Path(tableDir, "_balancedSplit");
FileSystem fs = FileSystem.get(conf);
// get a list of daughter regions to create
LinkedList<Pair<byte[], byte[]>> tmpRegionSet = getSplits(table, splitAlgo);
LinkedList<Pair<byte[], byte[]>> outstanding = Lists.newLinkedList();
int splitCount = 0;
final int origCount = tmpRegionSet.size();
// all splits must compact & we have 1 compact thread, so 2 split
// requests to the same RS can stall the outstanding split queue.
// To fix, group the regions into an RS pool and round-robin through it
LOG.debug("Bucketing regions by regionserver...");
TreeMap<HServerAddress, LinkedList<Pair<byte[], byte[]>>> daughterRegions = Maps
.newTreeMap();
for (Pair<byte[], byte[]> dr : tmpRegionSet) {
HServerAddress rsLocation = table.getRegionLocation(dr.getSecond())
.getServerAddress();
if (!daughterRegions.containsKey(rsLocation)) {
LinkedList<Pair<byte[], byte[]>> entry = Lists.newLinkedList();
daughterRegions.put(rsLocation, entry);
}
daughterRegions.get(rsLocation).add(dr);
}
LOG.debug("Done with bucketing. Split time!");
long startTime = System.currentTimeMillis();
// open the split file and modify it as splits finish
FSDataInputStream tmpIn = fs.open(splitFile);
byte[] rawData = new byte[tmpIn.available()];
tmpIn.readFully(rawData);
tmpIn.close();
FSDataOutputStream splitOut = fs.create(splitFile);
splitOut.write(rawData);
try {
// *** split code ***
while (!daughterRegions.isEmpty()) {
LOG.debug(daughterRegions.size() + " RS have regions to splt.");
// round-robin through the RS list
for (HServerAddress rsLoc = daughterRegions.firstKey();
rsLoc != null;
rsLoc = daughterRegions.higherKey(rsLoc)) {
Pair<byte[], byte[]> dr = null;
// find a region in the RS list that hasn't been moved
LOG.debug("Finding a region on " + rsLoc);
LinkedList<Pair<byte[], byte[]>> regionList = daughterRegions
.get(rsLoc);
while (!regionList.isEmpty()) {
dr = regionList.pop();
// get current region info
byte[] split = dr.getSecond();
HRegionLocation regionLoc = table.getRegionLocation(split);
// if this region moved locations
HServerAddress newRs = regionLoc.getServerAddress();
if (newRs.compareTo(rsLoc) != 0) {
LOG.debug("Region with " + splitAlgo.rowToStr(split)
+ " moved to " + newRs + ". Relocating...");
// relocate it, don't use it right now
if (!daughterRegions.containsKey(newRs)) {
LinkedList<Pair<byte[], byte[]>> entry = Lists.newLinkedList();
daughterRegions.put(newRs, entry);
}
daughterRegions.get(newRs).add(dr);
dr = null;
continue;
}
// make sure this region wasn't already split
byte[] sk = regionLoc.getRegionInfo().getStartKey();
if (sk.length != 0) {
if (Bytes.equals(split, sk)) {
LOG.debug("Region already split on "
+ splitAlgo.rowToStr(split) + ". Skipping this region...");
dr = null;
continue;
}
byte[] start = dr.getFirst();
Preconditions.checkArgument(Bytes.equals(start, sk), splitAlgo
.rowToStr(start) + " != " + splitAlgo.rowToStr(sk));
}
// passed all checks! found a good region
break;
}
if (regionList.isEmpty()) {
daughterRegions.remove(rsLoc);
}
if (dr == null)
continue;
// we have a good region, time to split!
byte[] start = dr.getFirst();
byte[] split = dr.getSecond();
// request split
LOG.debug("Splitting at " + splitAlgo.rowToStr(split));
HBaseAdmin admin = new HBaseAdmin(table.getConfiguration());
admin.split(table.getTableName(), split);
if (conf.getBoolean("split.verify", true)) {
// wait for one of the daughter regions to come online
boolean daughterOnline = false;
int daughterSleep = 5; // seconds
while (!daughterOnline) {
LOG.debug("Waiting for daughter region to come online...");
table.clearRegionCache();
HRegionInfo hri = table.getRegionLocation(split).getRegionInfo();
daughterOnline = Bytes.equals(hri.getStartKey(), split)
&& !hri.isOffline();
daughterSleep = Math.min(daughterSleep * 2, 60);
Thread.sleep(daughterSleep * 1000); // sleep
}
LOG.debug("Daughter region is online.");
}
// mark the region as successfully split.
// NOTE: split done, but daughter regions still need to major compact
splitOut.writeChars("- " + splitAlgo.rowToStr(dr.getFirst()) + " "
+ splitAlgo.rowToStr(dr.getSecond()) + "\n");
splitCount++;
if (splitCount % 10 == 0) {
long tDiff = (System.currentTimeMillis() - startTime) / splitCount;
LOG.debug("STATUS UPDATE: " + splitCount + " / " + origCount
+ ". Avg Time / Split = "
+ org.apache.hadoop.util.StringUtils.formatTime(tDiff));
}
if (conf.getBoolean("split.verify", true)) {
// if we have too many outstanding splits, wait for oldest ones to
// finish
outstanding.addLast(Pair.newPair(start, split));
if (outstanding.size() > MAX_OUTSTANDING) {
Pair<byte[], byte[]> reg = outstanding.removeFirst();
String outStart = splitAlgo.rowToStr(reg.getFirst());
String outSplit = splitAlgo.rowToStr(reg.getSecond());
LOG.debug("Waiting for " + outStart + " , " + outSplit
+ " to finish compaction");
// when a daughter region is opened, a compaction is triggered
// wait until compaction completes for both daughter regions
LinkedList<HRegionInfo> check = Lists.newLinkedList();
// figure out where this region should be in HDFS
check
.add(table.getRegionLocation(reg.getFirst()).getRegionInfo());
check.add(table.getRegionLocation(reg.getSecond())
.getRegionInfo());
while (!check.isEmpty()) {
// compaction is completed when all reference files are gone
for (HRegionInfo hri : check.toArray(new HRegionInfo[] {})) {
boolean refFound = false;
byte[] sk = hri.getStartKey();
if (sk.length == 0)
sk = splitAlgo.firstRow();
String startKey = splitAlgo.rowToStr(sk);
// check every Column Family for that region
for (HColumnDescriptor c : hri.getTableDesc().getFamilies()) {
Path cfDir = Store.getStoreHomedir(tableDir, hri
.getEncodedName(), c.getName());
if (fs.exists(cfDir)) {
for (FileStatus file : fs.listStatus(cfDir)) {
refFound |= StoreFile.isReference(file.getPath());
if (refFound) {
LOG.debug("Reference still exists for " + startKey
+ " at " + file.getPath());
break;
}
}
}
if (refFound)
break;
}
if (!refFound) {
check.remove(hri);
LOG.debug("- finished compaction of " + startKey);
}
}
// sleep in between requests
if (!check.isEmpty()) {
LOG.debug("Waiting for " + check.size() + " compactions");
Thread.sleep(30 * 1000);
}
}
}
}
}
}
LOG.debug("All regions have been sucesfully split!");
} finally {
long tDiff = System.currentTimeMillis() - startTime;
LOG.debug("TOTAL TIME = "
+ org.apache.hadoop.util.StringUtils.formatTime(tDiff));
LOG.debug("Splits = " + splitCount);
LOG.debug("Avg Time / Split = "
+ org.apache.hadoop.util.StringUtils.formatTime(tDiff / splitCount));
splitOut.close();
}
fs.delete(splitFile, false);
}
static LinkedList<Pair<byte[], byte[]>> getSplits(HTable table,
SplitAlgorithm splitAlgo) throws IOException {
Path hbDir = new Path(table.getConfiguration().get(HConstants.HBASE_DIR));
Path tableDir = HTableDescriptor.getTableDir(hbDir, table.getTableName());
Path splitFile = new Path(tableDir, "_balancedSplit");
FileSystem fs = FileSystem.get(table.getConfiguration());
// using strings because (new byte[]{0}).equals(new byte[]{0}) == false
Set<Pair<String, String>> daughterRegions = Sets.newHashSet();
// does a split file exist?
if (!fs.exists(splitFile)) {
// NO = fresh start. calculate splits to make
LOG.debug("No _balancedSplit file. Calculating splits...");
// query meta for all regions in the table
Set<Pair<byte[], byte[]>> rows = Sets.newHashSet();
Pair<byte[][], byte[][]> tmp = table.getStartEndKeys();
Preconditions.checkArgument(
tmp.getFirst().length == tmp.getSecond().length,
"Start and End rows should be equivalent");
for (int i = 0; i < tmp.getFirst().length; ++i) {
byte[] start = tmp.getFirst()[i], end = tmp.getSecond()[i];
if (start.length == 0)
start = splitAlgo.firstRow();
if (end.length == 0)
end = splitAlgo.lastRow();
rows.add(Pair.newPair(start, end));
}
LOG.debug("Table " + Bytes.toString(table.getTableName()) + " has "
+ rows.size() + " regions that will be split.");
// prepare the split file
Path tmpFile = new Path(tableDir, "_balancedSplit_prepare");
FSDataOutputStream tmpOut = fs.create(tmpFile);
// calculate all the splits == [daughterRegions] = [(start, splitPoint)]
for (Pair<byte[], byte[]> r : rows) {
byte[] splitPoint = splitAlgo.split(r.getFirst(), r.getSecond());
String startStr = splitAlgo.rowToStr(r.getFirst());
String splitStr = splitAlgo.rowToStr(splitPoint);
daughterRegions.add(Pair.newPair(startStr, splitStr));
LOG.debug("Will Split [" + startStr + " , "
+ splitAlgo.rowToStr(r.getSecond()) + ") at " + splitStr);
tmpOut.writeChars("+ " + startStr + splitAlgo.separator() + splitStr
+ "\n");
}
tmpOut.close();
fs.rename(tmpFile, splitFile);
} else {
LOG.debug("_balancedSplit file found. Replay log to restore state...");
FSUtils.recoverFileLease(fs, splitFile, table.getConfiguration());
// parse split file and process remaining splits
FSDataInputStream tmpIn = fs.open(splitFile);
StringBuilder sb = new StringBuilder(tmpIn.available());
while (tmpIn.available() > 0) {
sb.append(tmpIn.readChar());
}
tmpIn.close();
for (String line : sb.toString().split("\n")) {
String[] cmd = line.split(splitAlgo.separator());
Preconditions.checkArgument(3 == cmd.length);
byte[] start = splitAlgo.strToRow(cmd[1]);
String startStr = splitAlgo.rowToStr(start);
byte[] splitPoint = splitAlgo.strToRow(cmd[2]);
String splitStr = splitAlgo.rowToStr(splitPoint);
Pair<String, String> r = Pair.newPair(startStr, splitStr);
if (cmd[0].equals("+")) {
LOG.debug("Adding: " + r);
daughterRegions.add(r);
} else {
LOG.debug("Removing: " + r);
Preconditions.checkArgument(cmd[0].equals("-"),
"Unknown option: " + cmd[0]);
Preconditions.checkState(daughterRegions.contains(r),
"Missing row: " + r);
daughterRegions.remove(r);
}
}
LOG.debug("Done reading. " + daughterRegions.size() + " regions left.");
}
LinkedList<Pair<byte[], byte[]>> ret = Lists.newLinkedList();
for (Pair<String, String> r : daughterRegions) {
ret.add(Pair.newPair(splitAlgo.strToRow(r.getFirst()), splitAlgo
.strToRow(r.getSecond())));
}
return ret;
}
/**
* MD5StringSplit is the default {@link SplitAlgorithm} for creating pre-split
* tables. The format of MD5StringSplit is the ASCII representation of an MD5
* checksum. Row are long values in the range <b>"00000000" => "7FFFFFFF"</b>
* and are left-padded with zeros to keep the same order lexographically as if
* they were binary.
*/
public static class MD5StringSplit implements SplitAlgorithm {
final static String MAXMD5 = "7FFFFFFF";
final static BigInteger MAXMD5_INT = new BigInteger(MAXMD5, 16);
final static int rowComparisonLength = MAXMD5.length();
public byte[] split(byte[] start, byte[] end) {
BigInteger s = convertToBigInteger(start);
BigInteger e = convertToBigInteger(end);
Preconditions.checkArgument(!e.equals(BigInteger.ZERO));
return convertToByte(split2(s, e));
}
public byte[][] split(int n) {
BigInteger[] splits = new BigInteger[n - 1];
BigInteger sizeOfEachSplit = MAXMD5_INT.divide(BigInteger.valueOf(n));
for (int i = 1; i < n; i++) {
// NOTE: this means the last region gets all the slop.
// This is not a big deal if we're assuming n << MAXMD5
splits[i - 1] = sizeOfEachSplit.multiply(BigInteger.valueOf(i));
}
return convertToBytes(splits);
}
public byte[] firstRow() {
return convertToByte(BigInteger.ZERO);
}
public byte[] lastRow() {
return convertToByte(MAXMD5_INT);
}
public byte[] strToRow(String in) {
return convertToByte(new BigInteger(in, 16));
}
public String rowToStr(byte[] row) {
return Bytes.toStringBinary(row);
}
public String separator() {
return " ";
}
static BigInteger split2(BigInteger minValue, BigInteger maxValue) {
return maxValue.add(minValue).divide(BigInteger.valueOf(2));
}
/**
* Returns an array of bytes corresponding to an array of BigIntegers
*
* @param bigIntegers
* @return bytes corresponding to the bigIntegers
*/
static byte[][] convertToBytes(BigInteger[] bigIntegers) {
byte[][] returnBytes = new byte[bigIntegers.length][];
for (int i = 0; i < bigIntegers.length; i++) {
returnBytes[i] = convertToByte(bigIntegers[i]);
}
return returnBytes;
}
/**
* Returns the bytes corresponding to the BigInteger
*
* @param bigInteger
* @return byte corresponding to input BigInteger
*/
static byte[] convertToByte(BigInteger bigInteger) {
String bigIntegerString = bigInteger.toString(16);
bigIntegerString = StringUtils.leftPad(bigIntegerString,
rowComparisonLength, '0');
return Bytes.toBytes(bigIntegerString);
}
/**
* Returns the BigInteger represented by thebyte array
*
* @param row
* @return the corresponding BigInteger
*/
static BigInteger convertToBigInteger(byte[] row) {
return (row.length > 0) ? new BigInteger(Bytes.toString(row), 16)
: BigInteger.ZERO;
}
}
}