Java tutorial
/** * 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.tool; import static java.lang.String.format; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InterruptedIOException; import java.nio.ByteBuffer; import java.util.ArrayDeque; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.Deque; import java.util.HashMap; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Map.Entry; import java.util.Optional; import java.util.Set; import java.util.SortedMap; import java.util.TreeMap; import java.util.UUID; import java.util.concurrent.Callable; import java.util.concurrent.ExecutionException; import java.util.concurrent.ExecutorService; import java.util.concurrent.Future; import java.util.concurrent.LinkedBlockingQueue; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicInteger; import java.util.stream.Collectors; import org.apache.commons.lang3.mutable.MutableInt; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.fs.permission.FsPermission; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.HConstants; import org.apache.hadoop.hbase.TableName; import org.apache.hadoop.hbase.TableNotFoundException; import org.apache.hadoop.hbase.client.Admin; import org.apache.hadoop.hbase.client.ClientServiceCallable; import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor; import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder; import org.apache.hadoop.hbase.client.Connection; import org.apache.hadoop.hbase.client.ConnectionFactory; import org.apache.hadoop.hbase.client.RegionLocator; import org.apache.hadoop.hbase.client.RpcRetryingCallerFactory; import org.apache.hadoop.hbase.client.SecureBulkLoadClient; import org.apache.hadoop.hbase.client.Table; import org.apache.hadoop.hbase.client.TableDescriptorBuilder; import org.apache.hadoop.hbase.io.HFileLink; import org.apache.hadoop.hbase.io.HalfStoreFileReader; import org.apache.hadoop.hbase.io.Reference; import org.apache.hadoop.hbase.io.compress.Compression.Algorithm; import org.apache.hadoop.hbase.io.hfile.CacheConfig; import org.apache.hadoop.hbase.io.hfile.HFile; import org.apache.hadoop.hbase.io.hfile.HFileContext; import org.apache.hadoop.hbase.io.hfile.HFileContextBuilder; import org.apache.hadoop.hbase.io.hfile.HFileDataBlockEncoder; import org.apache.hadoop.hbase.io.hfile.HFileScanner; import org.apache.hadoop.hbase.ipc.RpcControllerFactory; import org.apache.hadoop.hbase.regionserver.BloomType; import org.apache.hadoop.hbase.regionserver.HStore; import org.apache.hadoop.hbase.regionserver.StoreFileInfo; import org.apache.hadoop.hbase.regionserver.StoreFileWriter; import org.apache.hadoop.hbase.security.UserProvider; import org.apache.hadoop.hbase.security.token.FsDelegationToken; import org.apache.hadoop.hbase.util.Bytes; import org.apache.hadoop.hbase.util.FSHDFSUtils; import org.apache.hadoop.hbase.util.FSVisitor; import org.apache.hadoop.hbase.util.Pair; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; import org.apache.yetus.audience.InterfaceAudience; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.apache.hbase.thirdparty.com.google.common.annotations.VisibleForTesting; import org.apache.hbase.thirdparty.com.google.common.collect.HashMultimap; import org.apache.hbase.thirdparty.com.google.common.collect.Lists; import org.apache.hbase.thirdparty.com.google.common.collect.Maps; import org.apache.hbase.thirdparty.com.google.common.collect.Multimap; import org.apache.hbase.thirdparty.com.google.common.collect.Multimaps; import org.apache.hbase.thirdparty.com.google.common.util.concurrent.ThreadFactoryBuilder; /** * Tool to load the output of HFileOutputFormat into an existing table. * @deprecated since 2.2.0, will be removed in 3.0.0. Use {@link BulkLoadHFiles} instead. Please * rewrite your code if you rely on methods other than the {@link #run(Map, TableName)} * and {@link #run(String, TableName)}, as all the methods other than them will be * removed with no replacement. */ @Deprecated @InterfaceAudience.Public public class LoadIncrementalHFiles extends Configured implements Tool { private static final Logger LOG = LoggerFactory.getLogger(LoadIncrementalHFiles.class); /** * @deprecated since 2.2.0, will be removed in 3.0.0, with no replacement. End user should not * depend on this value. */ @Deprecated public static final String NAME = BulkLoadHFilesTool.NAME; static final String RETRY_ON_IO_EXCEPTION = BulkLoadHFiles.RETRY_ON_IO_EXCEPTION; public static final String MAX_FILES_PER_REGION_PER_FAMILY = BulkLoadHFiles.MAX_FILES_PER_REGION_PER_FAMILY; private static final String ASSIGN_SEQ_IDS = BulkLoadHFiles.ASSIGN_SEQ_IDS; public final static String CREATE_TABLE_CONF_KEY = BulkLoadHFiles.CREATE_TABLE_CONF_KEY; public final static String IGNORE_UNMATCHED_CF_CONF_KEY = BulkLoadHFiles.IGNORE_UNMATCHED_CF_CONF_KEY; public final static String ALWAYS_COPY_FILES = BulkLoadHFiles.ALWAYS_COPY_FILES; // We use a '.' prefix which is ignored when walking directory trees // above. It is invalid family name. static final String TMP_DIR = ".tmp"; private final int maxFilesPerRegionPerFamily; private final boolean assignSeqIds; // Source delegation token private final FsDelegationToken fsDelegationToken; private final UserProvider userProvider; private final int nrThreads; private AtomicInteger numRetries; private final RpcControllerFactory rpcControllerFactory; private String bulkToken; /** * Represents an HFile waiting to be loaded. An queue is used in this class in order to support * the case where a region has split during the process of the load. When this happens, the HFile * is split into two physical parts across the new region boundary, and each part is added back * into the queue. The import process finishes when the queue is empty. * @deprecated Use {@link BulkLoadHFiles} instead. */ @InterfaceAudience.Public @Deprecated public static class LoadQueueItem extends BulkLoadHFiles.LoadQueueItem { public LoadQueueItem(byte[] family, Path hfilePath) { super(family, hfilePath); } } public LoadIncrementalHFiles(Configuration conf) { // make a copy, just to be sure we're not overriding someone else's config super(HBaseConfiguration.create(conf)); conf = getConf(); // disable blockcache for tool invocation, see HBASE-10500 conf.setFloat(HConstants.HFILE_BLOCK_CACHE_SIZE_KEY, 0); userProvider = UserProvider.instantiate(conf); fsDelegationToken = new FsDelegationToken(userProvider, "renewer"); assignSeqIds = conf.getBoolean(ASSIGN_SEQ_IDS, true); maxFilesPerRegionPerFamily = conf.getInt(MAX_FILES_PER_REGION_PER_FAMILY, 32); nrThreads = conf.getInt("hbase.loadincremental.threads.max", Runtime.getRuntime().availableProcessors()); numRetries = new AtomicInteger(0); rpcControllerFactory = new RpcControllerFactory(conf); } private void usage() { System.err.println("usage: " + "bin/hbase completebulkload <-Dargs> " + "</path/to/hfileoutputformat-output> <tablename>\n" + "\t-D" + CREATE_TABLE_CONF_KEY + "=no can be used to avoid creation " + "of a table by this tool.\n" + "\t Note: if you set this to 'no', then target table must already exist.\n" + "\t-D" + IGNORE_UNMATCHED_CF_CONF_KEY + "=yes can be used to ignore " + "unmatched column families.\n" + "\t-loadTable switch implies your baseDirectory to store file has a " + "depth of 3, table must exist\n" + "\t and -loadTable switch is the last option on the command line.\n\n"); } /** * Prepare a collection of {@link LoadQueueItem} from list of source hfiles contained in the * passed directory and validates whether the prepared queue has all the valid table column * families in it. * @param hfilesDir directory containing list of hfiles to be loaded into the table * @param table table to which hfiles should be loaded * @param queue queue which needs to be loaded into the table * @param validateHFile if true hfiles will be validated for its format * @throws IOException If any I/O or network error occurred */ public void prepareHFileQueue(Path hfilesDir, Table table, Deque<LoadQueueItem> queue, boolean validateHFile) throws IOException { prepareHFileQueue(hfilesDir, table, queue, validateHFile, false); } /** * Prepare a collection of {@link LoadQueueItem} from list of source hfiles contained in the * passed directory and validates whether the prepared queue has all the valid table column * families in it. * @param hfilesDir directory containing list of hfiles to be loaded into the table * @param table table to which hfiles should be loaded * @param queue queue which needs to be loaded into the table * @param validateHFile if true hfiles will be validated for its format * @param silence true to ignore unmatched column families * @throws IOException If any I/O or network error occurred */ public void prepareHFileQueue(Path hfilesDir, Table table, Deque<LoadQueueItem> queue, boolean validateHFile, boolean silence) throws IOException { discoverLoadQueue(queue, hfilesDir, validateHFile); validateFamiliesInHFiles(table, queue, silence); } /** * Prepare a collection of {@link LoadQueueItem} from list of source hfiles contained in the * passed directory and validates whether the prepared queue has all the valid table column * families in it. * @param map map of family to List of hfiles * @param table table to which hfiles should be loaded * @param queue queue which needs to be loaded into the table * @param silence true to ignore unmatched column families * @throws IOException If any I/O or network error occurred */ public void prepareHFileQueue(Map<byte[], List<Path>> map, Table table, Deque<LoadQueueItem> queue, boolean silence) throws IOException { populateLoadQueue(queue, map); validateFamiliesInHFiles(table, queue, silence); } /** * Perform a bulk load of the given directory into the given pre-existing table. This method is * not threadsafe. * @param hfofDir the directory that was provided as the output path of a job using * HFileOutputFormat * @param admin the Admin * @param table the table to load into * @param regionLocator region locator * @throws TableNotFoundException if table does not yet exist */ public Map<LoadQueueItem, ByteBuffer> doBulkLoad(Path hfofDir, final Admin admin, Table table, RegionLocator regionLocator) throws TableNotFoundException, IOException { return doBulkLoad(hfofDir, admin, table, regionLocator, false, false); } /** * Perform a bulk load of the given directory into the given pre-existing table. This method is * not threadsafe. * @param map map of family to List of hfiles * @param admin the Admin * @param table the table to load into * @param regionLocator region locator * @param silence true to ignore unmatched column families * @param copyFile always copy hfiles if true * @throws TableNotFoundException if table does not yet exist */ public Map<LoadQueueItem, ByteBuffer> doBulkLoad(Map<byte[], List<Path>> map, final Admin admin, Table table, RegionLocator regionLocator, boolean silence, boolean copyFile) throws TableNotFoundException, IOException { if (!admin.isTableAvailable(regionLocator.getName())) { throw new TableNotFoundException("Table " + table.getName() + " is not currently available."); } // LQI queue does not need to be threadsafe -- all operations on this queue // happen in this thread Deque<LoadQueueItem> queue = new ArrayDeque<>(); ExecutorService pool = null; SecureBulkLoadClient secureClient = null; try { prepareHFileQueue(map, table, queue, silence); if (queue.isEmpty()) { LOG.warn("Bulk load operation did not get any files to load"); return Collections.emptyMap(); } pool = createExecutorService(); secureClient = new SecureBulkLoadClient(table.getConfiguration(), table); return performBulkLoad(admin, table, regionLocator, queue, pool, secureClient, copyFile); } finally { cleanup(admin, queue, pool, secureClient); } } /** * Perform a bulk load of the given directory into the given pre-existing table. This method is * not threadsafe. * @param hfofDir the directory that was provided as the output path of a job using * HFileOutputFormat * @param admin the Admin * @param table the table to load into * @param regionLocator region locator * @param silence true to ignore unmatched column families * @param copyFile always copy hfiles if true * @throws TableNotFoundException if table does not yet exist */ public Map<LoadQueueItem, ByteBuffer> doBulkLoad(Path hfofDir, final Admin admin, Table table, RegionLocator regionLocator, boolean silence, boolean copyFile) throws TableNotFoundException, IOException { if (!admin.isTableAvailable(regionLocator.getName())) { throw new TableNotFoundException("Table " + table.getName() + " is not currently available."); } /* * Checking hfile format is a time-consuming operation, we should have an option to skip this * step when bulkloading millions of HFiles. See HBASE-13985. */ boolean validateHFile = getConf().getBoolean("hbase.loadincremental.validate.hfile", true); if (!validateHFile) { LOG.warn("You are skipping HFiles validation, it might cause some data loss if files " + "are not correct. If you fail to read data from your table after using this " + "option, consider removing the files and bulkload again without this option. " + "See HBASE-13985"); } // LQI queue does not need to be threadsafe -- all operations on this queue // happen in this thread Deque<LoadQueueItem> queue = new ArrayDeque<>(); ExecutorService pool = null; SecureBulkLoadClient secureClient = null; try { prepareHFileQueue(hfofDir, table, queue, validateHFile, silence); if (queue.isEmpty()) { LOG.warn( "Bulk load operation did not find any files to load in directory {}. " + "Does it contain files in subdirectories that correspond to column family names?", (hfofDir != null ? hfofDir.toUri().toString() : "")); return Collections.emptyMap(); } pool = createExecutorService(); secureClient = new SecureBulkLoadClient(table.getConfiguration(), table); return performBulkLoad(admin, table, regionLocator, queue, pool, secureClient, copyFile); } finally { cleanup(admin, queue, pool, secureClient); } } /** * Used by the replication sink to load the hfiles from the source cluster. It does the following, * <ol> * <li>LoadIncrementalHFiles#groupOrSplitPhase(Table, ExecutorService, Deque, Pair)}</li> * <li>LoadIncrementalHFiles#bulkLoadPhase(Table, Connection, ExecutorService, Deque, Multimap) * </li> * </ol> * @param table Table to which these hfiles should be loaded to * @param conn Connection to use * @param queue {@link LoadQueueItem} has hfiles yet to be loaded * @param startEndKeys starting and ending row keys of the region */ public void loadHFileQueue(Table table, Connection conn, Deque<LoadQueueItem> queue, Pair<byte[][], byte[][]> startEndKeys) throws IOException { loadHFileQueue(table, conn, queue, startEndKeys, false); } /** * Used by the replication sink to load the hfiles from the source cluster. It does the following, * <ol> * <li>LoadIncrementalHFiles#groupOrSplitPhase(Table, ExecutorService, Deque, Pair)}</li> * <li>LoadIncrementalHFiles#bulkLoadPhase(Table, Connection, ExecutorService, Deque, Multimap) * </li> * </ol> * @param table Table to which these hfiles should be loaded to * @param conn Connection to use * @param queue {@link LoadQueueItem} has hfiles yet to be loaded * @param startEndKeys starting and ending row keys of the region */ public void loadHFileQueue(Table table, Connection conn, Deque<LoadQueueItem> queue, Pair<byte[][], byte[][]> startEndKeys, boolean copyFile) throws IOException { ExecutorService pool = null; try { pool = createExecutorService(); Multimap<ByteBuffer, LoadQueueItem> regionGroups = groupOrSplitPhase(table, pool, queue, startEndKeys) .getFirst(); bulkLoadPhase(table, conn, pool, queue, regionGroups, copyFile, null); } finally { if (pool != null) { pool.shutdown(); } } } private Map<LoadQueueItem, ByteBuffer> performBulkLoad(Admin admin, Table table, RegionLocator regionLocator, Deque<LoadQueueItem> queue, ExecutorService pool, SecureBulkLoadClient secureClient, boolean copyFile) throws IOException { int count = 0; fsDelegationToken.acquireDelegationToken(queue.peek().getFilePath().getFileSystem(getConf())); bulkToken = secureClient.prepareBulkLoad(admin.getConnection()); Pair<Multimap<ByteBuffer, LoadQueueItem>, Set<String>> pair = null; Map<LoadQueueItem, ByteBuffer> item2RegionMap = new HashMap<>(); // Assumes that region splits can happen while this occurs. while (!queue.isEmpty()) { // need to reload split keys each iteration. final Pair<byte[][], byte[][]> startEndKeys = regionLocator.getStartEndKeys(); if (count != 0) { LOG.info("Split occurred while grouping HFiles, retry attempt " + count + " with " + queue.size() + " files remaining to group or split"); } int maxRetries = getConf().getInt(HConstants.BULKLOAD_MAX_RETRIES_NUMBER, 10); maxRetries = Math.max(maxRetries, startEndKeys.getFirst().length + 1); if (maxRetries != 0 && count >= maxRetries) { throw new IOException("Retry attempted " + count + " times without completing, bailing out"); } count++; // Using ByteBuffer for byte[] equality semantics pair = groupOrSplitPhase(table, pool, queue, startEndKeys); Multimap<ByteBuffer, LoadQueueItem> regionGroups = pair.getFirst(); if (!checkHFilesCountPerRegionPerFamily(regionGroups)) { // Error is logged inside checkHFilesCountPerRegionPerFamily. throw new IOException("Trying to load more than " + maxFilesPerRegionPerFamily + " hfiles to one family of one region"); } bulkLoadPhase(table, admin.getConnection(), pool, queue, regionGroups, copyFile, item2RegionMap); // NOTE: The next iteration's split / group could happen in parallel to // atomic bulkloads assuming that there are splits and no merges, and // that we can atomically pull out the groups we want to retry. } if (!queue.isEmpty()) { throw new RuntimeException( "Bulk load aborted with some files not yet loaded." + "Please check log for more details."); } return item2RegionMap; } /** * This takes the LQI's grouped by likely regions and attempts to bulk load them. Any failures are * re-queued for another pass with the groupOrSplitPhase. * <p> * protected for testing. */ @VisibleForTesting protected void bulkLoadPhase(Table table, Connection conn, ExecutorService pool, Deque<LoadQueueItem> queue, Multimap<ByteBuffer, LoadQueueItem> regionGroups, boolean copyFile, Map<LoadQueueItem, ByteBuffer> item2RegionMap) throws IOException { // atomically bulk load the groups. Set<Future<List<LoadQueueItem>>> loadingFutures = new HashSet<>(); for (Entry<ByteBuffer, ? extends Collection<LoadQueueItem>> e : regionGroups.asMap().entrySet()) { byte[] first = e.getKey().array(); Collection<LoadQueueItem> lqis = e.getValue(); ClientServiceCallable<byte[]> serviceCallable = buildClientServiceCallable(conn, table.getName(), first, lqis, copyFile); Callable<List<LoadQueueItem>> call = new Callable<List<LoadQueueItem>>() { @Override public List<LoadQueueItem> call() throws Exception { List<LoadQueueItem> toRetry = tryAtomicRegionLoad(serviceCallable, table.getName(), first, lqis); return toRetry; } }; if (item2RegionMap != null) { for (LoadQueueItem lqi : lqis) { item2RegionMap.put(lqi, e.getKey()); } } loadingFutures.add(pool.submit(call)); } // get all the results. for (Future<List<LoadQueueItem>> future : loadingFutures) { try { List<LoadQueueItem> toRetry = future.get(); if (item2RegionMap != null) { for (LoadQueueItem lqi : toRetry) { item2RegionMap.remove(lqi); } } // LQIs that are requeued to be regrouped. queue.addAll(toRetry); } catch (ExecutionException e1) { Throwable t = e1.getCause(); if (t instanceof IOException) { // At this point something unrecoverable has happened. // TODO Implement bulk load recovery throw new IOException("BulkLoad encountered an unrecoverable problem", t); } LOG.error("Unexpected execution exception during bulk load", e1); throw new IllegalStateException(t); } catch (InterruptedException e1) { LOG.error("Unexpected interrupted exception during bulk load", e1); throw (InterruptedIOException) new InterruptedIOException().initCause(e1); } } } @VisibleForTesting protected ClientServiceCallable<byte[]> buildClientServiceCallable(Connection conn, TableName tableName, byte[] first, Collection<LoadQueueItem> lqis, boolean copyFile) { List<Pair<byte[], String>> famPaths = lqis.stream() .map(lqi -> Pair.newPair(lqi.getFamily(), lqi.getFilePath().toString())) .collect(Collectors.toList()); return new ClientServiceCallable<byte[]>(conn, tableName, first, rpcControllerFactory.newController(), HConstants.PRIORITY_UNSET) { @Override protected byte[] rpcCall() throws Exception { SecureBulkLoadClient secureClient = null; boolean success = false; try { if (LOG.isDebugEnabled()) { LOG.debug("Going to connect to server " + getLocation() + " for row " + Bytes.toStringBinary(getRow()) + " with hfile group " + LoadIncrementalHFiles.this.toString(famPaths)); } byte[] regionName = getLocation().getRegion().getRegionName(); try (Table table = conn.getTable(getTableName())) { secureClient = new SecureBulkLoadClient(getConf(), table); success = secureClient.secureBulkLoadHFiles(getStub(), famPaths, regionName, assignSeqIds, fsDelegationToken.getUserToken(), bulkToken, copyFile); } return success ? regionName : null; } finally { // Best effort copying of files that might not have been imported // from the staging directory back to original location // in user directory if (secureClient != null && !success) { FileSystem targetFs = FileSystem.get(getConf()); FileSystem sourceFs = lqis.iterator().next().getFilePath().getFileSystem(getConf()); // Check to see if the source and target filesystems are the same // If they are the same filesystem, we will try move the files back // because previously we moved them to the staging directory. if (FSHDFSUtils.isSameHdfs(getConf(), sourceFs, targetFs)) { for (Pair<byte[], String> el : famPaths) { Path hfileStagingPath = null; Path hfileOrigPath = new Path(el.getSecond()); try { hfileStagingPath = new Path(new Path(bulkToken, Bytes.toString(el.getFirst())), hfileOrigPath.getName()); if (targetFs.rename(hfileStagingPath, hfileOrigPath)) { LOG.debug("Moved back file " + hfileOrigPath + " from " + hfileStagingPath); } else if (targetFs.exists(hfileStagingPath)) { LOG.debug("Unable to move back file " + hfileOrigPath + " from " + hfileStagingPath); } } catch (Exception ex) { LOG.debug("Unable to move back file " + hfileOrigPath + " from " + hfileStagingPath, ex); } } } } } } }; } private boolean checkHFilesCountPerRegionPerFamily(final Multimap<ByteBuffer, LoadQueueItem> regionGroups) { for (Map.Entry<ByteBuffer, Collection<LoadQueueItem>> e : regionGroups.asMap().entrySet()) { Map<byte[], MutableInt> filesMap = new TreeMap<>(Bytes.BYTES_COMPARATOR); for (LoadQueueItem lqi : e.getValue()) { MutableInt count = filesMap.computeIfAbsent(lqi.getFamily(), k -> new MutableInt()); count.increment(); if (count.intValue() > maxFilesPerRegionPerFamily) { LOG.error("Trying to load more than " + maxFilesPerRegionPerFamily + " hfiles to family " + Bytes.toStringBinary(lqi.getFamily()) + " of region with start key " + Bytes.toStringBinary(e.getKey())); return false; } } } return true; } /** * @param table the table to load into * @param pool the ExecutorService * @param queue the queue for LoadQueueItem * @param startEndKeys start and end keys * @return A map that groups LQI by likely bulk load region targets and Set of missing hfiles. */ private Pair<Multimap<ByteBuffer, LoadQueueItem>, Set<String>> groupOrSplitPhase(final Table table, ExecutorService pool, Deque<LoadQueueItem> queue, final Pair<byte[][], byte[][]> startEndKeys) throws IOException { // <region start key, LQI> need synchronized only within this scope of this // phase because of the puts that happen in futures. Multimap<ByteBuffer, LoadQueueItem> rgs = HashMultimap.create(); final Multimap<ByteBuffer, LoadQueueItem> regionGroups = Multimaps.synchronizedMultimap(rgs); Set<String> missingHFiles = new HashSet<>(); Pair<Multimap<ByteBuffer, LoadQueueItem>, Set<String>> pair = new Pair<>(regionGroups, missingHFiles); // drain LQIs and figure out bulk load groups Set<Future<Pair<List<LoadQueueItem>, String>>> splittingFutures = new HashSet<>(); while (!queue.isEmpty()) { final LoadQueueItem item = queue.remove(); final Callable<Pair<List<LoadQueueItem>, String>> call = new Callable<Pair<List<LoadQueueItem>, String>>() { @Override public Pair<List<LoadQueueItem>, String> call() throws Exception { Pair<List<LoadQueueItem>, String> splits = groupOrSplit(regionGroups, item, table, startEndKeys); return splits; } }; splittingFutures.add(pool.submit(call)); } // get all the results. All grouping and splitting must finish before // we can attempt the atomic loads. for (Future<Pair<List<LoadQueueItem>, String>> lqis : splittingFutures) { try { Pair<List<LoadQueueItem>, String> splits = lqis.get(); if (splits != null) { if (splits.getFirst() != null) { queue.addAll(splits.getFirst()); } else { missingHFiles.add(splits.getSecond()); } } } catch (ExecutionException e1) { Throwable t = e1.getCause(); if (t instanceof IOException) { LOG.error("IOException during splitting", e1); throw (IOException) t; // would have been thrown if not parallelized, } LOG.error("Unexpected execution exception during splitting", e1); throw new IllegalStateException(t); } catch (InterruptedException e1) { LOG.error("Unexpected interrupted exception during splitting", e1); throw (InterruptedIOException) new InterruptedIOException().initCause(e1); } } return pair; } private List<LoadQueueItem> splitStoreFile(final LoadQueueItem item, final Table table, byte[] startKey, byte[] splitKey) throws IOException { Path hfilePath = item.getFilePath(); byte[] family = item.getFamily(); Path tmpDir = hfilePath.getParent(); if (!tmpDir.getName().equals(TMP_DIR)) { tmpDir = new Path(tmpDir, TMP_DIR); } LOG.info("HFile at " + hfilePath + " no longer fits inside a single " + "region. Splitting..."); String uniqueName = getUniqueName(); ColumnFamilyDescriptor familyDesc = table.getDescriptor().getColumnFamily(family); Path botOut = new Path(tmpDir, uniqueName + ".bottom"); Path topOut = new Path(tmpDir, uniqueName + ".top"); splitStoreFile(getConf(), hfilePath, familyDesc, splitKey, botOut, topOut); FileSystem fs = tmpDir.getFileSystem(getConf()); fs.setPermission(tmpDir, FsPermission.valueOf("-rwxrwxrwx")); fs.setPermission(botOut, FsPermission.valueOf("-rwxrwxrwx")); fs.setPermission(topOut, FsPermission.valueOf("-rwxrwxrwx")); // Add these back at the *front* of the queue, so there's a lower // chance that the region will just split again before we get there. List<LoadQueueItem> lqis = new ArrayList<>(2); lqis.add(new LoadQueueItem(family, botOut)); lqis.add(new LoadQueueItem(family, topOut)); // If the current item is already the result of previous splits, // we don't need it anymore. Clean up to save space. // It is not part of the original input files. try { if (tmpDir.getName().equals(TMP_DIR)) { fs.delete(hfilePath, false); } } catch (IOException e) { LOG.warn("Unable to delete temporary split file " + hfilePath); } LOG.info("Successfully split into new HFiles " + botOut + " and " + topOut); return lqis; } /** * Attempt to assign the given load queue item into its target region group. If the hfile boundary * no longer fits into a region, physically splits the hfile such that the new bottom half will * fit and returns the list of LQI's corresponding to the resultant hfiles. * <p> * protected for testing * @throws IOException if an IO failure is encountered */ @VisibleForTesting protected Pair<List<LoadQueueItem>, String> groupOrSplit(Multimap<ByteBuffer, LoadQueueItem> regionGroups, final LoadQueueItem item, final Table table, final Pair<byte[][], byte[][]> startEndKeys) throws IOException { Path hfilePath = item.getFilePath(); Optional<byte[]> first, last; try (HFile.Reader hfr = HFile.createReader(hfilePath.getFileSystem(getConf()), hfilePath, CacheConfig.DISABLED, true, getConf())) { hfr.loadFileInfo(); first = hfr.getFirstRowKey(); last = hfr.getLastRowKey(); } catch (FileNotFoundException fnfe) { LOG.debug("encountered", fnfe); return new Pair<>(null, hfilePath.getName()); } LOG.info("Trying to load hfile=" + hfilePath + " first=" + first.map(Bytes::toStringBinary) + " last=" + last.map(Bytes::toStringBinary)); if (!first.isPresent() || !last.isPresent()) { assert !first.isPresent() && !last.isPresent(); // TODO what if this is due to a bad HFile? LOG.info("hfile " + hfilePath + " has no entries, skipping"); return null; } if (Bytes.compareTo(first.get(), last.get()) > 0) { throw new IllegalArgumentException("Invalid range: " + Bytes.toStringBinary(first.get()) + " > " + Bytes.toStringBinary(last.get())); } int idx = Arrays.binarySearch(startEndKeys.getFirst(), first.get(), Bytes.BYTES_COMPARATOR); if (idx < 0) { // not on boundary, returns -(insertion index). Calculate region it // would be in. idx = -(idx + 1) - 1; } int indexForCallable = idx; /** * we can consider there is a region hole in following conditions. 1) if idx < 0,then first * region info is lost. 2) if the endkey of a region is not equal to the startkey of the next * region. 3) if the endkey of the last region is not empty. */ if (indexForCallable < 0) { throw new IOException("The first region info for table " + table.getName() + " can't be found in hbase:meta.Please use hbck tool to fix it first."); } else if ((indexForCallable == startEndKeys.getFirst().length - 1) && !Bytes.equals(startEndKeys.getSecond()[indexForCallable], HConstants.EMPTY_BYTE_ARRAY)) { throw new IOException("The last region info for table " + table.getName() + " can't be found in hbase:meta.Please use hbck tool to fix it first."); } else if (indexForCallable + 1 < startEndKeys.getFirst().length && !(Bytes.compareTo(startEndKeys.getSecond()[indexForCallable], startEndKeys.getFirst()[indexForCallable + 1]) == 0)) { throw new IOException("The endkey of one region for table " + table.getName() + " is not equal to the startkey of the next region in hbase:meta." + "Please use hbck tool to fix it first."); } boolean lastKeyInRange = Bytes.compareTo(last.get(), startEndKeys.getSecond()[idx]) < 0 || Bytes.equals(startEndKeys.getSecond()[idx], HConstants.EMPTY_BYTE_ARRAY); if (!lastKeyInRange) { List<LoadQueueItem> lqis = splitStoreFile(item, table, startEndKeys.getFirst()[indexForCallable], startEndKeys.getSecond()[indexForCallable]); return new Pair<>(lqis, null); } // group regions. regionGroups.put(ByteBuffer.wrap(startEndKeys.getFirst()[idx]), item); return null; } /** * Attempts to do an atomic load of many hfiles into a region. If it fails, it returns a list of * hfiles that need to be retried. If it is successful it will return an empty list. * <p> * NOTE: To maintain row atomicity guarantees, region server callable should succeed atomically * and fails atomically. * <p> * Protected for testing. * @return empty list if success, list of items to retry on recoverable failure */ @VisibleForTesting protected List<LoadQueueItem> tryAtomicRegionLoad(ClientServiceCallable<byte[]> serviceCallable, final TableName tableName, final byte[] first, final Collection<LoadQueueItem> lqis) throws IOException { List<LoadQueueItem> toRetry = new ArrayList<>(); try { Configuration conf = getConf(); byte[] region = RpcRetryingCallerFactory.instantiate(conf, null).<byte[]>newCaller() .callWithRetries(serviceCallable, Integer.MAX_VALUE); if (region == null) { LOG.warn("Attempt to bulk load region containing " + Bytes.toStringBinary(first) + " into table " + tableName + " with files " + lqis + " failed. This is recoverable and they will be retried."); toRetry.addAll(lqis); // return lqi's to retry } // success return toRetry; } catch (IOException e) { LOG.error("Encountered unrecoverable error from region server, additional details: " + serviceCallable.getExceptionMessageAdditionalDetail(), e); LOG.warn("Received a " + e.getClass().getSimpleName() + " from region server: " + serviceCallable.getExceptionMessageAdditionalDetail(), e); if (getConf().getBoolean(RETRY_ON_IO_EXCEPTION, false) && numRetries.get() < getConf().getInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, HConstants.DEFAULT_HBASE_CLIENT_RETRIES_NUMBER)) { LOG.warn("Will attempt to retry loading failed HFiles. Retry #" + numRetries.incrementAndGet()); toRetry.addAll(lqis); return toRetry; } LOG.error(RETRY_ON_IO_EXCEPTION + " is disabled. Unable to recover"); throw e; } } /** * If the table is created for the first time, then "completebulkload" reads the files twice. More * modifications necessary if we want to avoid doing it. */ private void createTable(TableName tableName, Path hfofDir, Admin admin) throws IOException { final FileSystem fs = hfofDir.getFileSystem(getConf()); // Add column families // Build a set of keys List<ColumnFamilyDescriptorBuilder> familyBuilders = new ArrayList<>(); SortedMap<byte[], Integer> map = new TreeMap<>(Bytes.BYTES_COMPARATOR); visitBulkHFiles(fs, hfofDir, new BulkHFileVisitor<ColumnFamilyDescriptorBuilder>() { @Override public ColumnFamilyDescriptorBuilder bulkFamily(byte[] familyName) { ColumnFamilyDescriptorBuilder builder = ColumnFamilyDescriptorBuilder.newBuilder(familyName); familyBuilders.add(builder); return builder; } @Override public void bulkHFile(ColumnFamilyDescriptorBuilder builder, FileStatus hfileStatus) throws IOException { Path hfile = hfileStatus.getPath(); try (HFile.Reader reader = HFile.createReader(fs, hfile, CacheConfig.DISABLED, true, getConf())) { if (builder.getCompressionType() != reader.getFileContext().getCompression()) { builder.setCompressionType(reader.getFileContext().getCompression()); LOG.info("Setting compression " + reader.getFileContext().getCompression().name() + " for family " + builder.getNameAsString()); } reader.loadFileInfo(); byte[] first = reader.getFirstRowKey().get(); byte[] last = reader.getLastRowKey().get(); LOG.info("Trying to figure out region boundaries hfile=" + hfile + " first=" + Bytes.toStringBinary(first) + " last=" + Bytes.toStringBinary(last)); // To eventually infer start key-end key boundaries Integer value = map.containsKey(first) ? map.get(first) : 0; map.put(first, value + 1); value = map.containsKey(last) ? map.get(last) : 0; map.put(last, value - 1); } } }); byte[][] keys = inferBoundaries(map); TableDescriptorBuilder tdBuilder = TableDescriptorBuilder.newBuilder(tableName); familyBuilders.stream().map(ColumnFamilyDescriptorBuilder::build) .forEachOrdered(tdBuilder::setColumnFamily); admin.createTable(tdBuilder.build(), keys); LOG.info("Table " + tableName + " is available!!"); } private void cleanup(Admin admin, Deque<LoadQueueItem> queue, ExecutorService pool, SecureBulkLoadClient secureClient) throws IOException { fsDelegationToken.releaseDelegationToken(); if (bulkToken != null && secureClient != null) { secureClient.cleanupBulkLoad(admin.getConnection(), bulkToken); } if (pool != null) { pool.shutdown(); } if (!queue.isEmpty()) { StringBuilder err = new StringBuilder(); err.append("-------------------------------------------------\n"); err.append("Bulk load aborted with some files not yet loaded:\n"); err.append("-------------------------------------------------\n"); for (LoadQueueItem q : queue) { err.append(" ").append(q.getFilePath()).append('\n'); } LOG.error(err.toString()); } } // unique file name for the table private String getUniqueName() { return UUID.randomUUID().toString().replaceAll("-", ""); } /** * Checks whether there is any invalid family name in HFiles to be bulk loaded. */ private void validateFamiliesInHFiles(Table table, Deque<LoadQueueItem> queue, boolean silence) throws IOException { Set<String> familyNames = Arrays.asList(table.getDescriptor().getColumnFamilies()).stream() .map(f -> f.getNameAsString()).collect(Collectors.toSet()); List<String> unmatchedFamilies = queue.stream().map(item -> Bytes.toString(item.getFamily())) .filter(fn -> !familyNames.contains(fn)).distinct().collect(Collectors.toList()); if (unmatchedFamilies.size() > 0) { String msg = "Unmatched family names found: unmatched family names in HFiles to be bulkloaded: " + unmatchedFamilies + "; valid family names of table " + table.getName() + " are: " + familyNames; LOG.error(msg); if (!silence) { throw new IOException(msg); } } } /** * Populate the Queue with given HFiles */ private void populateLoadQueue(Deque<LoadQueueItem> ret, Map<byte[], List<Path>> map) { map.forEach((k, v) -> v.stream().map(p -> new LoadQueueItem(k, p)).forEachOrdered(ret::add)); } /** * Walk the given directory for all HFiles, and return a Queue containing all such files. */ private void discoverLoadQueue(final Deque<LoadQueueItem> ret, final Path hfofDir, final boolean validateHFile) throws IOException { visitBulkHFiles(hfofDir.getFileSystem(getConf()), hfofDir, new BulkHFileVisitor<byte[]>() { @Override public byte[] bulkFamily(final byte[] familyName) { return familyName; } @Override public void bulkHFile(final byte[] family, final FileStatus hfile) throws IOException { long length = hfile.getLen(); if (length > getConf().getLong(HConstants.HREGION_MAX_FILESIZE, HConstants.DEFAULT_MAX_FILE_SIZE)) { LOG.warn("Trying to bulk load hfile " + hfile.getPath() + " with size: " + length + " bytes can be problematic as it may lead to oversplitting."); } ret.add(new LoadQueueItem(family, hfile.getPath())); } }, validateHFile); } private interface BulkHFileVisitor<TFamily> { TFamily bulkFamily(byte[] familyName) throws IOException; void bulkHFile(TFamily family, FileStatus hfileStatus) throws IOException; } /** * Iterate over the bulkDir hfiles. Skip reference, HFileLink, files starting with "_" and * non-valid hfiles. */ private static <TFamily> void visitBulkHFiles(final FileSystem fs, final Path bulkDir, final BulkHFileVisitor<TFamily> visitor) throws IOException { visitBulkHFiles(fs, bulkDir, visitor, true); } /** * Iterate over the bulkDir hfiles. Skip reference, HFileLink, files starting with "_". Check and * skip non-valid hfiles by default, or skip this validation by setting * 'hbase.loadincremental.validate.hfile' to false. */ private static <TFamily> void visitBulkHFiles(FileSystem fs, Path bulkDir, BulkHFileVisitor<TFamily> visitor, boolean validateHFile) throws IOException { FileStatus[] familyDirStatuses = fs.listStatus(bulkDir); for (FileStatus familyStat : familyDirStatuses) { if (!familyStat.isDirectory()) { LOG.warn("Skipping non-directory " + familyStat.getPath()); continue; } Path familyDir = familyStat.getPath(); byte[] familyName = Bytes.toBytes(familyDir.getName()); // Skip invalid family try { ColumnFamilyDescriptorBuilder.isLegalColumnFamilyName(familyName); } catch (IllegalArgumentException e) { LOG.warn("Skipping invalid " + familyStat.getPath()); continue; } TFamily family = visitor.bulkFamily(familyName); FileStatus[] hfileStatuses = fs.listStatus(familyDir); for (FileStatus hfileStatus : hfileStatuses) { if (!fs.isFile(hfileStatus.getPath())) { LOG.warn("Skipping non-file " + hfileStatus); continue; } Path hfile = hfileStatus.getPath(); // Skip "_", reference, HFileLink String fileName = hfile.getName(); if (fileName.startsWith("_")) { continue; } if (StoreFileInfo.isReference(fileName)) { LOG.warn("Skipping reference " + fileName); continue; } if (HFileLink.isHFileLink(fileName)) { LOG.warn("Skipping HFileLink " + fileName); continue; } // Validate HFile Format if needed if (validateHFile) { try { if (!HFile.isHFileFormat(fs, hfile)) { LOG.warn("the file " + hfile + " doesn't seems to be an hfile. skipping"); continue; } } catch (FileNotFoundException e) { LOG.warn("the file " + hfile + " was removed"); continue; } } visitor.bulkHFile(family, hfileStatus); } } } // Initialize a thread pool private ExecutorService createExecutorService() { ThreadPoolExecutor pool = new ThreadPoolExecutor(nrThreads, nrThreads, 60, TimeUnit.SECONDS, new LinkedBlockingQueue<>(), new ThreadFactoryBuilder().setNameFormat("LoadIncrementalHFiles-%1$d").build()); pool.allowCoreThreadTimeOut(true); return pool; } private final String toString(List<Pair<byte[], String>> list) { StringBuilder sb = new StringBuilder(); sb.append('['); list.forEach(p -> { sb.append('{').append(Bytes.toStringBinary(p.getFirst())).append(',').append(p.getSecond()).append('}'); }); sb.append(']'); return sb.toString(); } /** * Split a storefile into a top and bottom half, maintaining the metadata, recreating bloom * filters, etc. */ @VisibleForTesting static void splitStoreFile(Configuration conf, Path inFile, ColumnFamilyDescriptor familyDesc, byte[] splitKey, Path bottomOut, Path topOut) throws IOException { // Open reader with no block cache, and not in-memory Reference topReference = Reference.createTopReference(splitKey); Reference bottomReference = Reference.createBottomReference(splitKey); copyHFileHalf(conf, inFile, topOut, topReference, familyDesc); copyHFileHalf(conf, inFile, bottomOut, bottomReference, familyDesc); } /** * Copy half of an HFile into a new HFile. */ private static void copyHFileHalf(Configuration conf, Path inFile, Path outFile, Reference reference, ColumnFamilyDescriptor familyDescriptor) throws IOException { FileSystem fs = inFile.getFileSystem(conf); CacheConfig cacheConf = CacheConfig.DISABLED; HalfStoreFileReader halfReader = null; StoreFileWriter halfWriter = null; try { halfReader = new HalfStoreFileReader(fs, inFile, cacheConf, reference, true, new AtomicInteger(0), true, conf); Map<byte[], byte[]> fileInfo = halfReader.loadFileInfo(); int blocksize = familyDescriptor.getBlocksize(); Algorithm compression = familyDescriptor.getCompressionType(); BloomType bloomFilterType = familyDescriptor.getBloomFilterType(); HFileContext hFileContext = new HFileContextBuilder().withCompression(compression) .withChecksumType(HStore.getChecksumType(conf)) .withBytesPerCheckSum(HStore.getBytesPerChecksum(conf)).withBlockSize(blocksize) .withDataBlockEncoding(familyDescriptor.getDataBlockEncoding()).withIncludesTags(true).build(); halfWriter = new StoreFileWriter.Builder(conf, cacheConf, fs).withFilePath(outFile) .withBloomType(bloomFilterType).withFileContext(hFileContext).build(); HFileScanner scanner = halfReader.getScanner(false, false, false); scanner.seekTo(); do { halfWriter.append(scanner.getCell()); } while (scanner.next()); for (Map.Entry<byte[], byte[]> entry : fileInfo.entrySet()) { if (shouldCopyHFileMetaKey(entry.getKey())) { halfWriter.appendFileInfo(entry.getKey(), entry.getValue()); } } } finally { if (halfReader != null) { try { halfReader.close(cacheConf.shouldEvictOnClose()); } catch (IOException e) { LOG.warn("failed to close hfile reader for " + inFile, e); } } if (halfWriter != null) { halfWriter.close(); } } } private static boolean shouldCopyHFileMetaKey(byte[] key) { // skip encoding to keep hfile meta consistent with data block info, see HBASE-15085 if (Bytes.equals(key, HFileDataBlockEncoder.DATA_BLOCK_ENCODING)) { return false; } return !HFile.isReservedFileInfoKey(key); } private boolean isCreateTable() { return "yes".equalsIgnoreCase(getConf().get(CREATE_TABLE_CONF_KEY, "yes")); } private boolean isSilence() { return "yes".equalsIgnoreCase(getConf().get(IGNORE_UNMATCHED_CF_CONF_KEY, "")); } private boolean isAlwaysCopyFiles() { return getConf().getBoolean(ALWAYS_COPY_FILES, false); } protected final Map<LoadQueueItem, ByteBuffer> run(Path hfofDir, TableName tableName) throws IOException { try (Connection connection = ConnectionFactory.createConnection(getConf()); Admin admin = connection.getAdmin()) { if (!admin.tableExists(tableName)) { if (isCreateTable()) { createTable(tableName, hfofDir, admin); } else { String errorMsg = format("Table '%s' does not exist.", tableName); LOG.error(errorMsg); throw new TableNotFoundException(errorMsg); } } try (Table table = connection.getTable(tableName); RegionLocator locator = connection.getRegionLocator(tableName)) { return doBulkLoad(hfofDir, admin, table, locator, isSilence(), isAlwaysCopyFiles()); } } } /** * Perform bulk load on the given table. * @param hfofDir the directory that was provided as the output path of a job using * HFileOutputFormat * @param tableName the table to load into */ public Map<LoadQueueItem, ByteBuffer> run(String hfofDir, TableName tableName) throws IOException { return run(new Path(hfofDir), tableName); } /** * Perform bulk load on the given table. * @param family2Files map of family to List of hfiles * @param tableName the table to load into */ public Map<LoadQueueItem, ByteBuffer> run(Map<byte[], List<Path>> family2Files, TableName tableName) throws IOException { try (Connection connection = ConnectionFactory.createConnection(getConf()); Admin admin = connection.getAdmin()) { if (!admin.tableExists(tableName)) { String errorMsg = format("Table '%s' does not exist.", tableName); LOG.error(errorMsg); throw new TableNotFoundException(errorMsg); } try (Table table = connection.getTable(tableName); RegionLocator locator = connection.getRegionLocator(tableName)) { return doBulkLoad(family2Files, admin, table, locator, isSilence(), isAlwaysCopyFiles()); } } } @Override public int run(String[] args) throws Exception { if (args.length != 2 && args.length != 3) { usage(); return -1; } String dirPath = args[0]; TableName tableName = TableName.valueOf(args[1]); if (args.length == 2) { return !run(dirPath, tableName).isEmpty() ? 0 : -1; } else { Map<byte[], List<Path>> family2Files = Maps.newHashMap(); FileSystem fs = FileSystem.get(getConf()); for (FileStatus regionDir : fs.listStatus(new Path(dirPath))) { FSVisitor.visitRegionStoreFiles(fs, regionDir.getPath(), (region, family, hfileName) -> { Path path = new Path(regionDir.getPath(), new Path(family, hfileName)); byte[] familyName = Bytes.toBytes(family); if (family2Files.containsKey(familyName)) { family2Files.get(familyName).add(path); } else { family2Files.put(familyName, Lists.newArrayList(path)); } }); } return !run(family2Files, tableName).isEmpty() ? 0 : -1; } } public static void main(String[] args) throws Exception { Configuration conf = HBaseConfiguration.create(); int ret = ToolRunner.run(conf, new LoadIncrementalHFiles(conf), args); System.exit(ret); } /** * Called from replication sink, where it manages bulkToken(staging directory) by itself. This is * used only when SecureBulkLoadEndpoint is configured in hbase.coprocessor.region.classes * property. This directory is used as a temporary directory where all files are initially * copied/moved from user given directory, set all the required file permissions and then from * their it is finally loaded into a table. This should be set only when, one would like to manage * the staging directory by itself. Otherwise this tool will handle this by itself. * @param stagingDir staging directory path */ public void setBulkToken(String stagingDir) { this.bulkToken = stagingDir; } /** * Infers region boundaries for a new table. * <p> * Parameter: <br> * bdryMap is a map between keys to an integer belonging to {+1, -1} * <ul> * <li>If a key is a start key of a file, then it maps to +1</li> * <li>If a key is an end key of a file, then it maps to -1</li> * </ul> * <p> * Algo:<br> * <ol> * <li>Poll on the keys in order: * <ol type="a"> * <li>Keep adding the mapped values to these keys (runningSum)</li> * <li>Each time runningSum reaches 0, add the start Key from when the runningSum had started to a * boundary list.</li> * </ol> * </li> * <li>Return the boundary list.</li> * </ol> */ public static byte[][] inferBoundaries(SortedMap<byte[], Integer> bdryMap) { List<byte[]> keysArray = new ArrayList<>(); int runningValue = 0; byte[] currStartKey = null; boolean firstBoundary = true; for (Map.Entry<byte[], Integer> item : bdryMap.entrySet()) { if (runningValue == 0) { currStartKey = item.getKey(); } runningValue += item.getValue(); if (runningValue == 0) { if (!firstBoundary) { keysArray.add(currStartKey); } firstBoundary = false; } } return keysArray.toArray(new byte[0][]); } }