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.wal; import static org.apache.hadoop.hbase.wal.WALSplitUtil.getCompletedRecoveredEditsFilePath; import static org.apache.hadoop.hbase.wal.WALSplitUtil.getRegionSplitEditsPath; import java.io.EOFException; import java.io.IOException; import java.io.InterruptedIOException; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.TreeMap; import java.util.concurrent.Callable; import java.util.concurrent.CompletionService; import java.util.concurrent.ExecutionException; import java.util.concurrent.ExecutorCompletionService; import java.util.concurrent.Future; import java.util.concurrent.ThreadFactory; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.hbase.Cell; import org.apache.hadoop.hbase.CellUtil; import org.apache.hadoop.hbase.HConstants; import org.apache.hadoop.hbase.log.HBaseMarkers; import org.apache.hadoop.hbase.util.Bytes; import org.apache.hadoop.hbase.util.FSUtils; import org.apache.hadoop.hbase.util.Threads; import org.apache.hadoop.io.MultipleIOException; import org.apache.hadoop.ipc.RemoteException; import org.apache.yetus.audience.InterfaceAudience; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.apache.hbase.thirdparty.com.google.common.base.Preconditions; import org.apache.hbase.thirdparty.com.google.common.collect.Lists; import org.apache.hbase.thirdparty.org.apache.commons.collections4.CollectionUtils; import org.apache.hbase.thirdparty.org.apache.commons.collections4.MapUtils; /** * Class that manages the output streams from the log splitting process. */ @InterfaceAudience.Private public class LogRecoveredEditsOutputSink extends OutputSink { private static final Logger LOG = LoggerFactory.getLogger(LogRecoveredEditsOutputSink.class); private WALSplitter walSplitter; private FileSystem walFS; private Configuration conf; public LogRecoveredEditsOutputSink(WALSplitter walSplitter, WALSplitter.PipelineController controller, EntryBuffers entryBuffers, int numWriters) { // More threads could potentially write faster at the expense // of causing more disk seeks as the logs are split. // 3. After a certain setting (probably around 3) the // process will be bound on the reader in the current // implementation anyway. super(controller, entryBuffers, numWriters); this.walSplitter = walSplitter; this.walFS = walSplitter.walFS; this.conf = walSplitter.conf; } /** * @return null if failed to report progress */ @Override public List<Path> finishWritingAndClose() throws IOException { boolean isSuccessful = false; List<Path> result = null; try { isSuccessful = finishWriting(false); } finally { result = close(); List<IOException> thrown = closeLogWriters(null); if (CollectionUtils.isNotEmpty(thrown)) { throw MultipleIOException.createIOException(thrown); } } if (isSuccessful) { splits = result; } return splits; } // delete the one with fewer wal entries private void deleteOneWithFewerEntries(WALSplitter.WriterAndPath wap, Path dst) throws IOException { long dstMinLogSeqNum = -1L; try (WAL.Reader reader = walSplitter.getWalFactory().createReader(walSplitter.walFS, dst)) { WAL.Entry entry = reader.next(); if (entry != null) { dstMinLogSeqNum = entry.getKey().getSequenceId(); } } catch (EOFException e) { LOG.debug("Got EOF when reading first WAL entry from {}, an empty or broken WAL file?", dst, e); } if (wap.minLogSeqNum < dstMinLogSeqNum) { LOG.warn("Found existing old edits file. It could be the result of a previous failed" + " split attempt or we have duplicated wal entries. Deleting " + dst + ", length=" + walFS.getFileStatus(dst).getLen()); if (!walFS.delete(dst, false)) { LOG.warn("Failed deleting of old {}", dst); throw new IOException("Failed deleting of old " + dst); } } else { LOG.warn("Found existing old edits file and we have less entries. Deleting " + wap.path + ", length=" + walFS.getFileStatus(wap.path).getLen()); if (!walFS.delete(wap.path, false)) { LOG.warn("Failed deleting of {}", wap.path); throw new IOException("Failed deleting of " + wap.path); } } } /** * Close all of the output streams. * @return the list of paths written. */ List<Path> close() throws IOException { Preconditions.checkState(!closeAndCleanCompleted); final List<Path> paths = new ArrayList<>(); final List<IOException> thrown = Lists.newArrayList(); ThreadPoolExecutor closeThreadPool = Threads.getBoundedCachedThreadPool(numThreads, 30L, TimeUnit.SECONDS, new ThreadFactory() { private int count = 1; @Override public Thread newThread(Runnable r) { Thread t = new Thread(r, "split-log-closeStream-" + count++); return t; } }); CompletionService<Void> completionService = new ExecutorCompletionService<>(closeThreadPool); boolean progress_failed; try { progress_failed = executeCloseTask(completionService, thrown, paths); } catch (InterruptedException e) { IOException iie = new InterruptedIOException(); iie.initCause(e); throw iie; } catch (ExecutionException e) { throw new IOException(e.getCause()); } finally { closeThreadPool.shutdownNow(); } if (!thrown.isEmpty()) { throw MultipleIOException.createIOException(thrown); } writersClosed = true; closeAndCleanCompleted = true; if (progress_failed) { return null; } return paths; } /** * @param completionService threadPool to execute the closing tasks * @param thrown store the exceptions * @param paths arrayList to store the paths written * @return if close tasks executed successful */ boolean executeCloseTask(CompletionService<Void> completionService, List<IOException> thrown, List<Path> paths) throws InterruptedException, ExecutionException { for (final Map.Entry<String, WALSplitter.SinkWriter> writersEntry : writers.entrySet()) { if (LOG.isTraceEnabled()) { LOG.trace("Submitting close of " + ((WALSplitter.WriterAndPath) writersEntry.getValue()).path); } completionService.submit(new Callable<Void>() { @Override public Void call() throws Exception { WALSplitter.WriterAndPath wap = (WALSplitter.WriterAndPath) writersEntry.getValue(); Path dst = closeWriter(writersEntry.getKey(), wap, thrown); paths.add(dst); return null; } }); } boolean progress_failed = false; for (int i = 0, n = this.writers.size(); i < n; i++) { Future<Void> future = completionService.take(); future.get(); if (!progress_failed && reporter != null && !reporter.progress()) { progress_failed = true; } } return progress_failed; } Path closeWriter(String encodedRegionName, WALSplitter.WriterAndPath wap, List<IOException> thrown) throws IOException { LOG.trace("Closing {}", wap.path); try { wap.writer.close(); } catch (IOException ioe) { LOG.error("Could not close log at {}", wap.path, ioe); thrown.add(ioe); return null; } if (LOG.isDebugEnabled()) { LOG.debug("Closed wap " + wap.path + " (wrote " + wap.editsWritten + " edits, skipped " + wap.editsSkipped + " edits in " + (wap.nanosSpent / 1000 / 1000) + "ms"); } if (wap.editsWritten == 0) { // just remove the empty recovered.edits file if (walFS.exists(wap.path) && !walFS.delete(wap.path, false)) { LOG.warn("Failed deleting empty {}", wap.path); throw new IOException("Failed deleting empty " + wap.path); } return null; } Path dst = getCompletedRecoveredEditsFilePath(wap.path, regionMaximumEditLogSeqNum.get(encodedRegionName)); try { if (!dst.equals(wap.path) && walFS.exists(dst)) { deleteOneWithFewerEntries(wap, dst); } // Skip the unit tests which create a splitter that reads and // writes the data without touching disk. // TestHLogSplit#testThreading is an example. if (walFS.exists(wap.path)) { if (!walFS.rename(wap.path, dst)) { throw new IOException("Failed renaming " + wap.path + " to " + dst); } LOG.info("Rename {} to {}", wap.path, dst); } } catch (IOException ioe) { LOG.error("Could not rename {} to {}", wap.path, dst, ioe); thrown.add(ioe); return null; } return dst; } private List<IOException> closeLogWriters(List<IOException> thrown) throws IOException { if (writersClosed) { return thrown; } if (thrown == null) { thrown = Lists.newArrayList(); } try { for (WriterThread writerThread : writerThreads) { while (writerThread.isAlive()) { writerThread.setShouldStop(true); writerThread.interrupt(); try { writerThread.join(10); } catch (InterruptedException e) { IOException iie = new InterruptedIOException(); iie.initCause(e); throw iie; } } } } finally { WALSplitter.WriterAndPath wap = null; for (WALSplitter.SinkWriter tmpWAP : writers.values()) { try { wap = (WALSplitter.WriterAndPath) tmpWAP; wap.writer.close(); } catch (IOException ioe) { LOG.error("Couldn't close log at {}", wap.path, ioe); thrown.add(ioe); continue; } LOG.info("Closed log " + wap.path + " (wrote " + wap.editsWritten + " edits in " + (wap.nanosSpent / 1000 / 1000) + "ms)"); } writersClosed = true; } return thrown; } /** * Get a writer and path for a log starting at the given entry. This function is threadsafe so * long as multiple threads are always acting on different regions. * @return null if this region shouldn't output any logs */ WALSplitter.WriterAndPath getWriterAndPath(WAL.Entry entry, boolean reusable) throws IOException { byte[] region = entry.getKey().getEncodedRegionName(); String regionName = Bytes.toString(region); WALSplitter.WriterAndPath ret = (WALSplitter.WriterAndPath) writers.get(regionName); if (ret != null) { return ret; } // If we already decided that this region doesn't get any output // we don't need to check again. if (blacklistedRegions.contains(region)) { return null; } ret = createWAP(region, entry); if (ret == null) { blacklistedRegions.add(region); return null; } if (reusable) { writers.put(regionName, ret); } return ret; } /** * @return a path with a write for that path. caller should close. */ WALSplitter.WriterAndPath createWAP(byte[] region, WAL.Entry entry) throws IOException { String tmpDirName = walSplitter.conf.get(HConstants.TEMPORARY_FS_DIRECTORY_KEY, HConstants.DEFAULT_TEMPORARY_HDFS_DIRECTORY); Path regionedits = getRegionSplitEditsPath(entry, walSplitter.getFileBeingSplit().getPath().getName(), tmpDirName, conf); if (regionedits == null) { return null; } FileSystem walFs = FSUtils.getWALFileSystem(conf); if (walFs.exists(regionedits)) { LOG.warn("Found old edits file. It could be the " + "result of a previous failed split attempt. Deleting " + regionedits + ", length=" + walFs.getFileStatus(regionedits).getLen()); if (!walFs.delete(regionedits, false)) { LOG.warn("Failed delete of old {}", regionedits); } } WALProvider.Writer w = walSplitter.createWriter(regionedits); LOG.debug("Creating writer path={}", regionedits); return new WALSplitter.WriterAndPath(regionedits, w, entry.getKey().getSequenceId()); } void filterCellByStore(WAL.Entry logEntry) { Map<byte[], Long> maxSeqIdInStores = walSplitter.getRegionMaxSeqIdInStores() .get(Bytes.toString(logEntry.getKey().getEncodedRegionName())); if (MapUtils.isEmpty(maxSeqIdInStores)) { return; } // Create the array list for the cells that aren't filtered. // We make the assumption that most cells will be kept. ArrayList<Cell> keptCells = new ArrayList<>(logEntry.getEdit().getCells().size()); for (Cell cell : logEntry.getEdit().getCells()) { if (CellUtil.matchingFamily(cell, WALEdit.METAFAMILY)) { keptCells.add(cell); } else { byte[] family = CellUtil.cloneFamily(cell); Long maxSeqId = maxSeqIdInStores.get(family); // Do not skip cell even if maxSeqId is null. Maybe we are in a rolling upgrade, // or the master was crashed before and we can not get the information. if (maxSeqId == null || maxSeqId.longValue() < logEntry.getKey().getSequenceId()) { keptCells.add(cell); } } } // Anything in the keptCells array list is still live. // So rather than removing the cells from the array list // which would be an O(n^2) operation, we just replace the list logEntry.getEdit().setCells(keptCells); } @Override public void append(WALSplitter.RegionEntryBuffer buffer) throws IOException { appendBuffer(buffer, true); } WALSplitter.WriterAndPath appendBuffer(WALSplitter.RegionEntryBuffer buffer, boolean reusable) throws IOException { List<WAL.Entry> entries = buffer.entryBuffer; if (entries.isEmpty()) { LOG.warn("got an empty buffer, skipping"); return null; } WALSplitter.WriterAndPath wap = null; long startTime = System.nanoTime(); try { int editsCount = 0; for (WAL.Entry logEntry : entries) { if (wap == null) { wap = getWriterAndPath(logEntry, reusable); if (wap == null) { // This log spews the full edit. Can be massive in the log. Enable only debugging // WAL lost edit issues. LOG.trace("getWriterAndPath decided we don't need to write edits for {}", logEntry); return null; } } filterCellByStore(logEntry); if (!logEntry.getEdit().isEmpty()) { wap.writer.append(logEntry); this.updateRegionMaximumEditLogSeqNum(logEntry); editsCount++; } else { wap.incrementSkippedEdits(1); } } // Pass along summary statistics wap.incrementEdits(editsCount); wap.incrementNanoTime(System.nanoTime() - startTime); } catch (IOException e) { e = e instanceof RemoteException ? ((RemoteException) e).unwrapRemoteException() : e; LOG.error(HBaseMarkers.FATAL, "Got while writing log entry to log", e); throw e; } return wap; } @Override public boolean keepRegionEvent(WAL.Entry entry) { ArrayList<Cell> cells = entry.getEdit().getCells(); for (Cell cell : cells) { if (WALEdit.isCompactionMarker(cell)) { return true; } } return false; } /** * @return a map from encoded region ID to the number of edits written out for that region. */ @Override public Map<byte[], Long> getOutputCounts() { TreeMap<byte[], Long> ret = new TreeMap<>(Bytes.BYTES_COMPARATOR); for (Map.Entry<String, WALSplitter.SinkWriter> entry : writers.entrySet()) { ret.put(Bytes.toBytes(entry.getKey()), entry.getValue().editsWritten); } return ret; } @Override public int getNumberOfRecoveredRegions() { return writers.size(); } }