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Posted to commits@hbase.apache.org by sy...@apache.org on 2016/03/30 18:03:41 UTC
[39/50] [abbrv] hbase git commit: HBASE-15265 Implement an
asynchronous FSHLog
http://git-wip-us.apache.org/repos/asf/hbase/blob/c96b642f/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/FSHLog.java
----------------------------------------------------------------------
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/FSHLog.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/FSHLog.java
index dfbdae5..67c2b93 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/FSHLog.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/FSHLog.java
@@ -17,62 +17,44 @@
*/
package org.apache.hadoop.hbase.regionserver.wal;
-import static org.apache.hadoop.hbase.wal.DefaultWALProvider.WAL_FILE_NAME_DELIMITER;
-
import java.io.FileNotFoundException;
import java.io.IOException;
-import java.io.InterruptedIOException;
import java.io.OutputStream;
-import java.lang.management.ManagementFactory;
-import java.lang.management.MemoryUsage;
-import java.lang.reflect.InvocationTargetException;
-import java.net.URLEncoder;
-import java.util.ArrayList;
import java.util.Arrays;
-import java.util.Comparator;
import java.util.List;
-import java.util.Map;
-import java.util.NavigableMap;
-import java.util.Set;
import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ConcurrentSkipListMap;
-import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.atomic.AtomicLong;
-import java.util.concurrent.locks.ReentrantLock;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.lmax.disruptor.BlockingWaitStrategy;
+import com.lmax.disruptor.EventHandler;
+import com.lmax.disruptor.ExceptionHandler;
+import com.lmax.disruptor.LifecycleAware;
+import com.lmax.disruptor.TimeoutException;
+import com.lmax.disruptor.dsl.Disruptor;
+import com.lmax.disruptor.dsl.ProducerType;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
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.fs.PathFilter;
-import org.apache.hadoop.hbase.Cell;
-import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
-import org.apache.hadoop.hbase.io.util.HeapMemorySizeUtil;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.ClassSize;
-import org.apache.hadoop.hbase.util.DrainBarrier;
-import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
import org.apache.hadoop.hbase.util.FSUtils;
import org.apache.hadoop.hbase.util.HasThread;
import org.apache.hadoop.hbase.util.Threads;
import org.apache.hadoop.hbase.wal.DefaultWALProvider;
-import org.apache.hadoop.hbase.wal.WAL;
import org.apache.hadoop.hbase.wal.WALFactory;
import org.apache.hadoop.hbase.wal.WALKey;
import org.apache.hadoop.hbase.wal.WALPrettyPrinter;
@@ -81,95 +63,59 @@ import org.apache.hadoop.hbase.wal.WALSplitter;
import org.apache.hadoop.hdfs.DFSOutputStream;
import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
-import org.apache.hadoop.util.StringUtils;
import org.apache.htrace.NullScope;
import org.apache.htrace.Span;
import org.apache.htrace.Trace;
import org.apache.htrace.TraceScope;
-import com.google.common.annotations.VisibleForTesting;
-import com.lmax.disruptor.BlockingWaitStrategy;
-import com.lmax.disruptor.EventHandler;
-import com.lmax.disruptor.ExceptionHandler;
-import com.lmax.disruptor.LifecycleAware;
-import com.lmax.disruptor.TimeoutException;
-import com.lmax.disruptor.dsl.Disruptor;
-import com.lmax.disruptor.dsl.ProducerType;
-
/**
- * Implementation of {@link WAL} to go against {@link FileSystem}; i.e. keep WALs in HDFS.
- * Only one WAL is ever being written at a time. When a WAL hits a configured maximum size,
- * it is rolled. This is done internal to the implementation.
- *
- * <p>As data is flushed from the MemStore to other on-disk structures (files sorted by
- * key, hfiles), a WAL becomes obsolete. We can let go of all the log edits/entries for a given
- * HRegion-sequence id. A bunch of work in the below is done keeping account of these region
- * sequence ids -- what is flushed out to hfiles, and what is yet in WAL and in memory only.
- *
- * <p>It is only practical to delete entire files. Thus, we delete an entire on-disk file
- * <code>F</code> when all of the edits in <code>F</code> have a log-sequence-id that's older
- * (smaller) than the most-recent flush.
- *
- * <p>To read an WAL, call {@link WALFactory#createReader(org.apache.hadoop.fs.FileSystem,
- * org.apache.hadoop.fs.Path)}.
- *
- * <h2>Failure Semantic</h2>
- * If an exception on append or sync, roll the WAL because the current WAL is now a lame duck;
- * any more appends or syncs will fail also with the same original exception. If we have made
- * successful appends to the WAL and we then are unable to sync them, our current semantic is to
- * return error to the client that the appends failed but also to abort the current context,
- * usually the hosting server. We need to replay the WALs. TODO: Change this semantic. A roll of
- * WAL may be sufficient as long as we have flagged client that the append failed. TODO:
- * replication may pick up these last edits though they have been marked as failed append (Need to
- * keep our own file lengths, not rely on HDFS).
+ * The default implementation of FSWAL.
*/
@InterfaceAudience.Private
-public class FSHLog implements WAL {
+public class FSHLog extends AbstractFSWAL<Writer> {
// IMPLEMENTATION NOTES:
//
- // At the core is a ring buffer. Our ring buffer is the LMAX Disruptor. It tries to
+ // At the core is a ring buffer. Our ring buffer is the LMAX Disruptor. It tries to
// minimize synchronizations and volatile writes when multiple contending threads as is the case
- // here appending and syncing on a single WAL. The Disruptor is configured to handle multiple
+ // here appending and syncing on a single WAL. The Disruptor is configured to handle multiple
// producers but it has one consumer only (the producers in HBase are IPC Handlers calling append
- // and then sync). The single consumer/writer pulls the appends and syncs off the ring buffer.
+ // and then sync). The single consumer/writer pulls the appends and syncs off the ring buffer.
// When a handler calls sync, it is given back a future. The producer 'blocks' on the future so
- // it does not return until the sync completes. The future is passed over the ring buffer from
+ // it does not return until the sync completes. The future is passed over the ring buffer from
// the producer/handler to the consumer thread where it does its best to batch up the producer
- // syncs so one WAL sync actually spans multiple producer sync invocations. How well the
+ // syncs so one WAL sync actually spans multiple producer sync invocations. How well the
// batching works depends on the write rate; i.e. we tend to batch more in times of
// high writes/syncs.
//
// Calls to append now also wait until the append has been done on the consumer side of the
- // disruptor. We used to not wait but it makes the implemenation easier to grok if we have
+ // disruptor. We used to not wait but it makes the implementation easier to grok if we have
// the region edit/sequence id after the append returns.
//
- // TODO: Handlers need to coordinate appending AND syncing. Can we have the threads contend
- // once only? Probably hard given syncs take way longer than an append.
+ // TODO: Handlers need to coordinate appending AND syncing. Can we have the threads contend
+ // once only? Probably hard given syncs take way longer than an append.
//
// The consumer threads pass the syncs off to multiple syncing threads in a round robin fashion
// to ensure we keep up back-to-back FS sync calls (FS sync calls are the long poll writing the
- // WAL). The consumer thread passes the futures to the sync threads for it to complete
+ // WAL). The consumer thread passes the futures to the sync threads for it to complete
// the futures when done.
//
- // The 'sequence' in the below is the sequence of the append/sync on the ringbuffer. It
- // acts as a sort-of transaction id. It is always incrementing.
+ // The 'sequence' in the below is the sequence of the append/sync on the ringbuffer. It
+ // acts as a sort-of transaction id. It is always incrementing.
//
- // The RingBufferEventHandler class hosts the ring buffer consuming code. The threads that
- // do the actual FS sync are implementations of SyncRunner. SafePointZigZagLatch is a
- // synchronization class used to halt the consumer at a safe point -- just after all outstanding
+ // The RingBufferEventHandler class hosts the ring buffer consuming code. The threads that
+ // do the actual FS sync are implementations of SyncRunner. SafePointZigZagLatch is a
+ // synchronization class used to halt the consumer at a safe point -- just after all outstanding
// syncs and appends have completed -- so the log roller can swap the WAL out under it.
-
+ //
+ // We use ring buffer sequence as txid of FSWALEntry and SyncFuture.
private static final Log LOG = LogFactory.getLog(FSHLog.class);
- private static final int DEFAULT_SLOW_SYNC_TIME_MS = 100; // in ms
-
/**
- * The nexus at which all incoming handlers meet. Does appends and sync with an ordering.
- * Appends and syncs are each put on the ring which means handlers need to
- * smash up against the ring twice (can we make it once only? ... maybe not since time to append
- * is so different from time to sync and sometimes we don't want to sync or we want to async
- * the sync). The ring is where we make sure of our ordering and it is also where we do
- * batching up of handler sync calls.
+ * The nexus at which all incoming handlers meet. Does appends and sync with an ordering. Appends
+ * and syncs are each put on the ring which means handlers need to smash up against the ring twice
+ * (can we make it once only? ... maybe not since time to append is so different from time to sync
+ * and sometimes we don't want to sync or we want to async the sync). The ring is where we make
+ * sure of our ordering and it is also where we do batching up of handler sync calls.
*/
private final Disruptor<RingBufferTruck> disruptor;
@@ -180,95 +126,13 @@ public class FSHLog implements WAL {
/**
* This fellow is run by the above appendExecutor service but it is all about batching up appends
- * and syncs; it may shutdown without cleaning out the last few appends or syncs. To guard
- * against this, keep a reference to this handler and do explicit close on way out to make sure
- * all flushed out before we exit.
+ * and syncs; it may shutdown without cleaning out the last few appends or syncs. To guard against
+ * this, keep a reference to this handler and do explicit close on way out to make sure all
+ * flushed out before we exit.
*/
private final RingBufferEventHandler ringBufferEventHandler;
/**
- * Map of {@link SyncFuture}s keyed by Handler objects. Used so we reuse SyncFutures.
- * TODO: Reus FSWALEntry's rather than create them anew each time as we do SyncFutures here.
- * TODO: Add a FSWalEntry and SyncFuture as thread locals on handlers rather than have them
- * get them from this Map?
- */
- private final Map<Thread, SyncFuture> syncFuturesByHandler;
-
- /**
- * The highest known outstanding unsync'd WALEdit sequence number where sequence number is the
- * ring buffer sequence. Maintained by the ring buffer consumer.
- */
- private volatile long highestUnsyncedSequence = -1;
-
- /**
- * Updated to the ring buffer sequence of the last successful sync call. This can be less than
- * {@link #highestUnsyncedSequence} for case where we have an append where a sync has not yet
- * come in for it. Maintained by the syncing threads.
- */
- private final AtomicLong highestSyncedSequence = new AtomicLong(0);
-
- /**
- * file system instance
- */
- protected final FileSystem fs;
-
- /**
- * WAL directory, where all WAL files would be placed.
- */
- private final Path fullPathLogDir;
-
- /**
- * dir path where old logs are kept.
- */
- private final Path fullPathArchiveDir;
-
- /**
- * Matches just those wal files that belong to this wal instance.
- */
- private final PathFilter ourFiles;
-
- /**
- * Prefix of a WAL file, usually the region server name it is hosted on.
- */
- private final String logFilePrefix;
-
- /**
- * Suffix included on generated wal file names
- */
- private final String logFileSuffix;
-
- /**
- * Prefix used when checking for wal membership.
- */
- private final String prefixPathStr;
-
- private final WALCoprocessorHost coprocessorHost;
-
- /**
- * conf object
- */
- protected final Configuration conf;
-
- /** Listeners that are called on WAL events. */
- private final List<WALActionsListener> listeners =
- new CopyOnWriteArrayList<WALActionsListener>();
-
- @Override
- public void registerWALActionsListener(final WALActionsListener listener) {
- this.listeners.add(listener);
- }
-
- @Override
- public boolean unregisterWALActionsListener(final WALActionsListener listener) {
- return this.listeners.remove(listener);
- }
-
- @Override
- public WALCoprocessorHost getCoprocessorHost() {
- return coprocessorHost;
- }
-
- /**
* FSDataOutputStream associated with the current SequenceFile.writer
*/
private FSDataOutputStream hdfs_out;
@@ -278,8 +142,6 @@ public class FSHLog implements WAL {
// Minimum tolerable replicas, if the actual value is lower than it, rollWriter will be triggered
private final int minTolerableReplication;
- private final int slowSyncNs;
-
// If live datanode count is lower than the default replicas value,
// RollWriter will be triggered in each sync(So the RollWriter will be
// triggered one by one in a short time). Using it as a workaround to slow
@@ -293,84 +155,14 @@ public class FSHLog implements WAL {
// Enable it if the replications recover.
private volatile boolean lowReplicationRollEnabled = true;
- /**
- * Class that does accounting of sequenceids in WAL subsystem. Holds oldest outstanding
- * sequence id as yet not flushed as well as the most recent edit sequence id appended to the
- * WAL. Has facility for answering questions such as "Is it safe to GC a WAL?".
- */
- private SequenceIdAccounting sequenceIdAccounting = new SequenceIdAccounting();
-
- /**
- * Current log file.
- */
- volatile Writer writer;
-
- /** The barrier used to ensure that close() waits for all log rolls and flushes to finish. */
- private final DrainBarrier closeBarrier = new DrainBarrier();
-
- /**
- * This lock makes sure only one log roll runs at a time. Should not be taken while any other
- * lock is held. We don't just use synchronized because that results in bogus and tedious
- * findbugs warning when it thinks synchronized controls writer thread safety. It is held when
- * we are actually rolling the log. It is checked when we are looking to see if we should roll
- * the log or not.
- */
- private final ReentrantLock rollWriterLock = new ReentrantLock(true);
-
- private volatile boolean closed = false;
- private final AtomicBoolean shutdown = new AtomicBoolean(false);
-
- // The timestamp (in ms) when the log file was created.
- private final AtomicLong filenum = new AtomicLong(-1);
-
- // Number of transactions in the current Wal.
- private final AtomicInteger numEntries = new AtomicInteger(0);
-
- // If > than this size, roll the log.
- private final long logrollsize;
-
- /**
- * The total size of wal
- */
- private AtomicLong totalLogSize = new AtomicLong(0);
-
- /*
- * If more than this many logs, force flush of oldest region to oldest edit
- * goes to disk. If too many and we crash, then will take forever replaying.
- * Keep the number of logs tidy.
- */
- private final int maxLogs;
-
/** Number of log close errors tolerated before we abort */
private final int closeErrorsTolerated;
private final AtomicInteger closeErrorCount = new AtomicInteger();
-
/**
- * WAL Comparator; it compares the timestamp (log filenum), present in the log file name.
- * Throws an IllegalArgumentException if used to compare paths from different wals.
- */
- final Comparator<Path> LOG_NAME_COMPARATOR = new Comparator<Path>() {
- @Override
- public int compare(Path o1, Path o2) {
- long t1 = getFileNumFromFileName(o1);
- long t2 = getFileNumFromFileName(o2);
- if (t1 == t2) return 0;
- return (t1 > t2) ? 1 : -1;
- }
- };
-
- /**
- * Map of WAL log file to the latest sequence ids of all regions it has entries of.
- * The map is sorted by the log file creation timestamp (contained in the log file name).
- */
- private NavigableMap<Path, Map<byte[], Long>> byWalRegionSequenceIds =
- new ConcurrentSkipListMap<Path, Map<byte[], Long>>(LOG_NAME_COMPARATOR);
-
- /**
- * Exception handler to pass the disruptor ringbuffer. Same as native implementation only it
- * logs using our logger instead of java native logger.
+ * Exception handler to pass the disruptor ringbuffer. Same as native implementation only it logs
+ * using our logger instead of java native logger.
*/
static class RingBufferExceptionHandler implements ExceptionHandler {
@Override
@@ -394,12 +186,10 @@ public class FSHLog implements WAL {
/**
* Constructor.
- *
* @param fs filesystem handle
* @param root path for stored and archived wals
* @param logDir dir where wals are stored
* @param conf configuration to use
- * @throws IOException
*/
public FSHLog(final FileSystem fs, final Path root, final String logDir, final Configuration conf)
throws IOException {
@@ -407,252 +197,79 @@ public class FSHLog implements WAL {
}
/**
- * Create an edit log at the given <code>dir</code> location.
- *
- * You should never have to load an existing log. If there is a log at
- * startup, it should have already been processed and deleted by the time the
- * WAL object is started up.
- *
+ * Create an edit log at the given <code>dir</code> location. You should never have to load an
+ * existing log. If there is a log at startup, it should have already been processed and deleted
+ * by the time the WAL object is started up.
* @param fs filesystem handle
* @param rootDir path to where logs and oldlogs
* @param logDir dir where wals are stored
* @param archiveDir dir where wals are archived
* @param conf configuration to use
- * @param listeners Listeners on WAL events. Listeners passed here will
- * be registered before we do anything else; e.g. the
- * Constructor {@link #rollWriter()}.
- * @param failIfWALExists If true IOException will be thrown if files related to this wal
- * already exist.
- * @param prefix should always be hostname and port in distributed env and
- * it will be URL encoded before being used.
- * If prefix is null, "wal" will be used
+ * @param listeners Listeners on WAL events. Listeners passed here will be registered before we do
+ * anything else; e.g. the Constructor {@link #rollWriter()}.
+ * @param failIfWALExists If true IOException will be thrown if files related to this wal already
+ * exist.
+ * @param prefix should always be hostname and port in distributed env and it will be URL encoded
+ * before being used. If prefix is null, "wal" will be used
* @param suffix will be url encoded. null is treated as empty. non-empty must start with
- * {@link DefaultWALProvider#WAL_FILE_NAME_DELIMITER}
- * @throws IOException
+ * {@link DefaultWALProvider#WAL_FILE_NAME_DELIMITER}
*/
public FSHLog(final FileSystem fs, final Path rootDir, final String logDir,
- final String archiveDir, final Configuration conf,
- final List<WALActionsListener> listeners,
- final boolean failIfWALExists, final String prefix, final String suffix)
- throws IOException {
- this.fs = fs;
- this.fullPathLogDir = new Path(rootDir, logDir);
- this.fullPathArchiveDir = new Path(rootDir, archiveDir);
- this.conf = conf;
-
- if (!fs.exists(fullPathLogDir) && !fs.mkdirs(fullPathLogDir)) {
- throw new IOException("Unable to mkdir " + fullPathLogDir);
- }
-
- if (!fs.exists(this.fullPathArchiveDir)) {
- if (!fs.mkdirs(this.fullPathArchiveDir)) {
- throw new IOException("Unable to mkdir " + this.fullPathArchiveDir);
- }
- }
-
- // If prefix is null||empty then just name it wal
- this.logFilePrefix =
- prefix == null || prefix.isEmpty() ? "wal" : URLEncoder.encode(prefix, "UTF8");
- // we only correctly differentiate suffices when numeric ones start with '.'
- if (suffix != null && !(suffix.isEmpty()) && !(suffix.startsWith(WAL_FILE_NAME_DELIMITER))) {
- throw new IllegalArgumentException("WAL suffix must start with '" + WAL_FILE_NAME_DELIMITER +
- "' but instead was '" + suffix + "'");
- }
- // Now that it exists, set the storage policy for the entire directory of wal files related to
- // this FSHLog instance
- FSUtils.setStoragePolicy(fs, conf, this.fullPathLogDir, HConstants.WAL_STORAGE_POLICY,
- HConstants.DEFAULT_WAL_STORAGE_POLICY);
- this.logFileSuffix = (suffix == null) ? "" : URLEncoder.encode(suffix, "UTF8");
- this.prefixPathStr = new Path(fullPathLogDir,
- logFilePrefix + WAL_FILE_NAME_DELIMITER).toString();
-
- this.ourFiles = new PathFilter() {
- @Override
- public boolean accept(final Path fileName) {
- // The path should start with dir/<prefix> and end with our suffix
- final String fileNameString = fileName.toString();
- if (!fileNameString.startsWith(prefixPathStr)) {
- return false;
- }
- if (logFileSuffix.isEmpty()) {
- // in the case of the null suffix, we need to ensure the filename ends with a timestamp.
- return org.apache.commons.lang.StringUtils.isNumeric(
- fileNameString.substring(prefixPathStr.length()));
- } else if (!fileNameString.endsWith(logFileSuffix)) {
- return false;
- }
- return true;
- }
- };
-
- if (failIfWALExists) {
- final FileStatus[] walFiles = FSUtils.listStatus(fs, fullPathLogDir, ourFiles);
- if (null != walFiles && 0 != walFiles.length) {
- throw new IOException("Target WAL already exists within directory " + fullPathLogDir);
- }
- }
-
- // Register listeners. TODO: Should this exist anymore? We have CPs?
- if (listeners != null) {
- for (WALActionsListener i: listeners) {
- registerWALActionsListener(i);
- }
- }
- this.coprocessorHost = new WALCoprocessorHost(this, conf);
-
- // Get size to roll log at. Roll at 95% of HDFS block size so we avoid crossing HDFS blocks
- // (it costs a little x'ing bocks)
- final long blocksize = this.conf.getLong("hbase.regionserver.hlog.blocksize",
- FSUtils.getDefaultBlockSize(this.fs, this.fullPathLogDir));
- this.logrollsize =
- (long)(blocksize * conf.getFloat("hbase.regionserver.logroll.multiplier", 0.95f));
-
- float memstoreRatio = conf.getFloat(HeapMemorySizeUtil.MEMSTORE_SIZE_KEY,
- conf.getFloat(HeapMemorySizeUtil.MEMSTORE_SIZE_OLD_KEY,
- HeapMemorySizeUtil.DEFAULT_MEMSTORE_SIZE));
- boolean maxLogsDefined = conf.get("hbase.regionserver.maxlogs") != null;
- if(maxLogsDefined){
- LOG.warn("'hbase.regionserver.maxlogs' was deprecated.");
- }
- this.maxLogs = conf.getInt("hbase.regionserver.maxlogs",
- Math.max(32, calculateMaxLogFiles(memstoreRatio, logrollsize)));
+ final String archiveDir, final Configuration conf, final List<WALActionsListener> listeners,
+ final boolean failIfWALExists, final String prefix, final String suffix) throws IOException {
+ super(fs, rootDir, logDir, archiveDir, conf, listeners, failIfWALExists, prefix, suffix);
this.minTolerableReplication = conf.getInt("hbase.regionserver.hlog.tolerable.lowreplication",
- FSUtils.getDefaultReplication(fs, this.fullPathLogDir));
- this.lowReplicationRollLimit =
- conf.getInt("hbase.regionserver.hlog.lowreplication.rolllimit", 5);
+ FSUtils.getDefaultReplication(fs, this.walDir));
+ this.lowReplicationRollLimit = conf.getInt("hbase.regionserver.hlog.lowreplication.rolllimit",
+ 5);
this.closeErrorsTolerated = conf.getInt("hbase.regionserver.logroll.errors.tolerated", 0);
- int maxHandlersCount = conf.getInt(HConstants.REGION_SERVER_HANDLER_COUNT, 200);
-
- LOG.info("WAL configuration: blocksize=" + StringUtils.byteDesc(blocksize) +
- ", rollsize=" + StringUtils.byteDesc(this.logrollsize) +
- ", prefix=" + this.logFilePrefix + ", suffix=" + logFileSuffix + ", logDir=" +
- this.fullPathLogDir + ", archiveDir=" + this.fullPathArchiveDir);
// rollWriter sets this.hdfs_out if it can.
rollWriter();
- this.slowSyncNs =
- 1000000 * conf.getInt("hbase.regionserver.hlog.slowsync.ms",
- DEFAULT_SLOW_SYNC_TIME_MS);
-
- // This is the 'writer' -- a single threaded executor. This single thread 'consumes' what is
+ // This is the 'writer' -- a single threaded executor. This single thread 'consumes' what is
// put on the ring buffer.
String hostingThreadName = Thread.currentThread().getName();
- this.appendExecutor = Executors.
- newSingleThreadExecutor(Threads.getNamedThreadFactory(hostingThreadName + ".append"));
- // Preallocate objects to use on the ring buffer. The way that appends and syncs work, we will
+ this.appendExecutor = Executors
+ .newSingleThreadExecutor(Threads.getNamedThreadFactory(hostingThreadName + ".append"));
+ // Preallocate objects to use on the ring buffer. The way that appends and syncs work, we will
// be stuck and make no progress if the buffer is filled with appends only and there is no
// sync. If no sync, then the handlers will be outstanding just waiting on sync completion
// before they return.
- final int preallocatedEventCount =
- this.conf.getInt("hbase.regionserver.wal.disruptor.event.count", 1024 * 16);
- // Using BlockingWaitStrategy. Stuff that is going on here takes so long it makes no sense
+ final int preallocatedEventCount = this.conf
+ .getInt("hbase.regionserver.wal.disruptor.event.count", 1024 * 16);
+ // Using BlockingWaitStrategy. Stuff that is going on here takes so long it makes no sense
// spinning as other strategies do.
- this.disruptor =
- new Disruptor<RingBufferTruck>(RingBufferTruck.EVENT_FACTORY, preallocatedEventCount,
- this.appendExecutor, ProducerType.MULTI, new BlockingWaitStrategy());
+ this.disruptor = new Disruptor<RingBufferTruck>(RingBufferTruck.EVENT_FACTORY,
+ preallocatedEventCount, this.appendExecutor, ProducerType.MULTI,
+ new BlockingWaitStrategy());
// Advance the ring buffer sequence so that it starts from 1 instead of 0,
// because SyncFuture.NOT_DONE = 0.
this.disruptor.getRingBuffer().next();
- this.ringBufferEventHandler =
- new RingBufferEventHandler(conf.getInt("hbase.regionserver.hlog.syncer.count", 5),
- maxHandlersCount);
+ int maxHandlersCount = conf.getInt(HConstants.REGION_SERVER_HANDLER_COUNT, 200);
+ this.ringBufferEventHandler = new RingBufferEventHandler(
+ conf.getInt("hbase.regionserver.hlog.syncer.count", 5), maxHandlersCount);
this.disruptor.handleExceptionsWith(new RingBufferExceptionHandler());
- this.disruptor.handleEventsWith(new RingBufferEventHandler [] {this.ringBufferEventHandler});
- // Presize our map of SyncFutures by handler objects.
- this.syncFuturesByHandler = new ConcurrentHashMap<Thread, SyncFuture>(maxHandlersCount);
+ this.disruptor.handleEventsWith(new RingBufferEventHandler[] { this.ringBufferEventHandler });
// Starting up threads in constructor is a no no; Interface should have an init call.
this.disruptor.start();
}
- private int calculateMaxLogFiles(float memstoreSizeRatio, long logRollSize) {
- MemoryUsage mu = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
- int maxLogs = Math.round(mu.getMax() * memstoreSizeRatio * 2 / logRollSize);
- return maxLogs;
- }
-
- /**
- * Get the backing files associated with this WAL.
- * @return may be null if there are no files.
- */
- protected FileStatus[] getFiles() throws IOException {
- return FSUtils.listStatus(fs, fullPathLogDir, ourFiles);
- }
-
/**
- * Currently, we need to expose the writer's OutputStream to tests so that they can manipulate
- * the default behavior (such as setting the maxRecoveryErrorCount value for example (see
+ * Currently, we need to expose the writer's OutputStream to tests so that they can manipulate the
+ * default behavior (such as setting the maxRecoveryErrorCount value for example (see
* {@link TestWALReplay#testReplayEditsWrittenIntoWAL()}). This is done using reflection on the
- * underlying HDFS OutputStream.
- * NOTE: This could be removed once Hadoop1 support is removed.
+ * underlying HDFS OutputStream. NOTE: This could be removed once Hadoop1 support is removed.
* @return null if underlying stream is not ready.
*/
@VisibleForTesting
OutputStream getOutputStream() {
FSDataOutputStream fsdos = this.hdfs_out;
- if (fsdos == null) return null;
- return fsdos.getWrappedStream();
- }
-
- @Override
- public byte [][] rollWriter() throws FailedLogCloseException, IOException {
- return rollWriter(false);
- }
-
- /**
- * retrieve the next path to use for writing.
- * Increments the internal filenum.
- */
- private Path getNewPath() throws IOException {
- this.filenum.set(System.currentTimeMillis());
- Path newPath = getCurrentFileName();
- while (fs.exists(newPath)) {
- this.filenum.incrementAndGet();
- newPath = getCurrentFileName();
- }
- return newPath;
- }
-
- Path getOldPath() {
- long currentFilenum = this.filenum.get();
- Path oldPath = null;
- if (currentFilenum > 0) {
- // ComputeFilename will take care of meta wal filename
- oldPath = computeFilename(currentFilenum);
- } // I presume if currentFilenum is <= 0, this is first file and null for oldPath if fine?
- return oldPath;
- }
-
- /**
- * Tell listeners about pre log roll.
- * @throws IOException
- */
- private void tellListenersAboutPreLogRoll(final Path oldPath, final Path newPath)
- throws IOException {
- if (!this.listeners.isEmpty()) {
- for (WALActionsListener i : this.listeners) {
- i.preLogRoll(oldPath, newPath);
- }
- }
- }
-
- /**
- * Tell listeners about post log roll.
- * @throws IOException
- */
- private void tellListenersAboutPostLogRoll(final Path oldPath, final Path newPath)
- throws IOException {
- if (!this.listeners.isEmpty()) {
- for (WALActionsListener i : this.listeners) {
- i.postLogRoll(oldPath, newPath);
- }
- }
+ return fsdos != null ? fsdos.getWrappedStream() : null;
}
/**
* Run a sync after opening to set up the pipeline.
- * @param nextWriter
- * @param startTimeNanos
*/
private void preemptiveSync(final ProtobufLogWriter nextWriter) {
long startTimeNanos = System.nanoTime();
@@ -665,115 +282,17 @@ public class FSHLog implements WAL {
}
}
- @Override
- public byte [][] rollWriter(boolean force) throws FailedLogCloseException, IOException {
- rollWriterLock.lock();
- try {
- // Return if nothing to flush.
- if (!force && (this.writer != null && this.numEntries.get() <= 0)) return null;
- byte [][] regionsToFlush = null;
- if (this.closed) {
- LOG.debug("WAL closed. Skipping rolling of writer");
- return regionsToFlush;
- }
- if (!closeBarrier.beginOp()) {
- LOG.debug("WAL closing. Skipping rolling of writer");
- return regionsToFlush;
- }
- TraceScope scope = Trace.startSpan("FSHLog.rollWriter");
- try {
- Path oldPath = getOldPath();
- Path newPath = getNewPath();
- // Any exception from here on is catastrophic, non-recoverable so we currently abort.
- Writer nextWriter = this.createWriterInstance(newPath);
- FSDataOutputStream nextHdfsOut = null;
- if (nextWriter instanceof ProtobufLogWriter) {
- nextHdfsOut = ((ProtobufLogWriter)nextWriter).getStream();
- // If a ProtobufLogWriter, go ahead and try and sync to force setup of pipeline.
- // If this fails, we just keep going.... it is an optimization, not the end of the world.
- preemptiveSync((ProtobufLogWriter)nextWriter);
- }
- tellListenersAboutPreLogRoll(oldPath, newPath);
- // NewPath could be equal to oldPath if replaceWriter fails.
- newPath = replaceWriter(oldPath, newPath, nextWriter, nextHdfsOut);
- tellListenersAboutPostLogRoll(oldPath, newPath);
- // Can we delete any of the old log files?
- if (getNumRolledLogFiles() > 0) {
- cleanOldLogs();
- regionsToFlush = findRegionsToForceFlush();
- }
- } finally {
- closeBarrier.endOp();
- assert scope == NullScope.INSTANCE || !scope.isDetached();
- scope.close();
- }
- return regionsToFlush;
- } finally {
- rollWriterLock.unlock();
- }
- }
-
/**
- * This method allows subclasses to inject different writers without having to
- * extend other methods like rollWriter().
- *
+ * This method allows subclasses to inject different writers without having to extend other
+ * methods like rollWriter().
* @return Writer instance
*/
protected Writer createWriterInstance(final Path path) throws IOException {
- return DefaultWALProvider.createWriter(conf, fs, path, false);
- }
-
- /**
- * Archive old logs. A WAL is eligible for archiving if all its WALEdits have been flushed.
- * @throws IOException
- */
- private void cleanOldLogs() throws IOException {
- List<Path> logsToArchive = null;
- // For each log file, look at its Map of regions to highest sequence id; if all sequence ids
- // are older than what is currently in memory, the WAL can be GC'd.
- for (Map.Entry<Path, Map<byte[], Long>> e : this.byWalRegionSequenceIds.entrySet()) {
- Path log = e.getKey();
- Map<byte[], Long> sequenceNums = e.getValue();
- if (this.sequenceIdAccounting.areAllLower(sequenceNums)) {
- if (logsToArchive == null) logsToArchive = new ArrayList<Path>();
- logsToArchive.add(log);
- if (LOG.isTraceEnabled()) LOG.trace("WAL file ready for archiving " + log);
- }
- }
- if (logsToArchive != null) {
- for (Path p : logsToArchive) {
- this.totalLogSize.addAndGet(-this.fs.getFileStatus(p).getLen());
- archiveLogFile(p);
- this.byWalRegionSequenceIds.remove(p);
- }
+ Writer writer = DefaultWALProvider.createWriter(conf, fs, path, false);
+ if (writer instanceof ProtobufLogWriter) {
+ preemptiveSync((ProtobufLogWriter) writer);
}
- }
-
- /**
- * If the number of un-archived WAL files is greater than maximum allowed, check the first
- * (oldest) WAL file, and returns those regions which should be flushed so that it can
- * be archived.
- * @return regions (encodedRegionNames) to flush in order to archive oldest WAL file.
- * @throws IOException
- */
- byte[][] findRegionsToForceFlush() throws IOException {
- byte [][] regions = null;
- int logCount = getNumRolledLogFiles();
- if (logCount > this.maxLogs && logCount > 0) {
- Map.Entry<Path, Map<byte[], Long>> firstWALEntry =
- this.byWalRegionSequenceIds.firstEntry();
- regions = this.sequenceIdAccounting.findLower(firstWALEntry.getValue());
- }
- if (regions != null) {
- StringBuilder sb = new StringBuilder();
- for (int i = 0; i < regions.length; i++) {
- if (i > 0) sb.append(", ");
- sb.append(Bytes.toStringBinary(regions[i]));
- }
- LOG.info("Too many WALs; count=" + logCount + ", max=" + this.maxLogs +
- "; forcing flush of " + regions.length + " regions(s): " + sb.toString());
- }
- return regions;
+ return writer;
}
/**
@@ -781,51 +300,39 @@ public class FSHLog implements WAL {
* @see #beforeWaitOnSafePoint()
*/
@VisibleForTesting
- protected void afterCreatingZigZagLatch() {}
+ protected void afterCreatingZigZagLatch() {
+ }
/**
* @see #afterCreatingZigZagLatch()
*/
@VisibleForTesting
- protected void beforeWaitOnSafePoint() {};
+ protected void beforeWaitOnSafePoint() {
+ };
- /**
- * Cleans up current writer closing it and then puts in place the passed in
- * <code>nextWriter</code>.
- *
- * In the case of creating a new WAL, oldPath will be null.
- *
- * In the case of rolling over from one file to the next, none of the params will be null.
- *
- * In the case of closing out this FSHLog with no further use newPath, nextWriter, and
- * nextHdfsOut will be null.
- *
- * @param oldPath may be null
- * @param newPath may be null
- * @param nextWriter may be null
- * @param nextHdfsOut may be null
- * @return the passed in <code>newPath</code>
- * @throws IOException if there is a problem flushing or closing the underlying FS
- */
- Path replaceWriter(final Path oldPath, final Path newPath, Writer nextWriter,
- final FSDataOutputStream nextHdfsOut)
- throws IOException {
- // Ask the ring buffer writer to pause at a safe point. Once we do this, the writer
+ @Override
+ protected void doAppend(Writer writer, FSWALEntry entry) throws IOException {
+ writer.append(entry);
+ }
+
+ @Override
+ protected long doReplaceWriter(Path oldPath, Path newPath, Writer nextWriter) throws IOException {
+ // Ask the ring buffer writer to pause at a safe point. Once we do this, the writer
// thread will eventually pause. An error hereafter needs to release the writer thread
- // regardless -- hence the finally block below. Note, this method is called from the FSHLog
+ // regardless -- hence the finally block below. Note, this method is called from the FSHLog
// constructor BEFORE the ring buffer is set running so it is null on first time through
// here; allow for that.
SyncFuture syncFuture = null;
- SafePointZigZagLatch zigzagLatch = (this.ringBufferEventHandler == null)?
- null: this.ringBufferEventHandler.attainSafePoint();
+ SafePointZigZagLatch zigzagLatch = (this.ringBufferEventHandler == null) ? null
+ : this.ringBufferEventHandler.attainSafePoint();
afterCreatingZigZagLatch();
- TraceScope scope = Trace.startSpan("FSHFile.replaceWriter");
+ long oldFileLen = 0L;
try {
- // Wait on the safe point to be achieved. Send in a sync in case nothing has hit the
+ // Wait on the safe point to be achieved. Send in a sync in case nothing has hit the
// ring buffer between the above notification of writer that we want it to go to
- // 'safe point' and then here where we are waiting on it to attain safe point. Use
+ // 'safe point' and then here where we are waiting on it to attain safe point. Use
// 'sendSync' instead of 'sync' because we do not want this thread to block waiting on it
- // to come back. Cleanup this syncFuture down below after we are ready to run again.
+ // to come back. Cleanup this syncFuture down below after we are ready to run again.
try {
if (zigzagLatch != null) {
Trace.addTimelineAnnotation("awaiting safepoint");
@@ -833,44 +340,37 @@ public class FSHLog implements WAL {
}
} catch (FailedSyncBeforeLogCloseException e) {
// If unflushed/unsynced entries on close, it is reason to abort.
- if (isUnflushedEntries()) throw e;
- LOG.warn("Failed sync-before-close but no outstanding appends; closing WAL: " +
- e.getMessage());
+ if (isUnflushedEntries()) {
+ throw e;
+ }
+ LOG.warn(
+ "Failed sync-before-close but no outstanding appends; closing WAL" + e.getMessage());
}
-
- // It is at the safe point. Swap out writer from under the blocked writer thread.
- // TODO: This is close is inline with critical section. Should happen in background?
- try {
- if (this.writer != null) {
+ // It is at the safe point. Swap out writer from under the blocked writer thread.
+ // TODO: This is close is inline with critical section. Should happen in background?
+ if (this.writer != null) {
+ oldFileLen = this.writer.getLength();
+ try {
Trace.addTimelineAnnotation("closing writer");
this.writer.close();
Trace.addTimelineAnnotation("writer closed");
- }
- this.closeErrorCount.set(0);
- } catch (IOException ioe) {
- int errors = closeErrorCount.incrementAndGet();
- if (!isUnflushedEntries() && (errors <= this.closeErrorsTolerated)) {
- LOG.warn("Riding over failed WAL close of " + oldPath + ", cause=\"" +
- ioe.getMessage() + "\", errors=" + errors +
- "; THIS FILE WAS NOT CLOSED BUT ALL EDITS SYNCED SO SHOULD BE OK");
- } else {
- throw ioe;
+ this.closeErrorCount.set(0);
+ } catch (IOException ioe) {
+ int errors = closeErrorCount.incrementAndGet();
+ if (!isUnflushedEntries() && (errors <= this.closeErrorsTolerated)) {
+ LOG.warn("Riding over failed WAL close of " + oldPath + ", cause=\"" + ioe.getMessage()
+ + "\", errors=" + errors
+ + "; THIS FILE WAS NOT CLOSED BUT ALL EDITS SYNCED SO SHOULD BE OK");
+ } else {
+ throw ioe;
+ }
}
}
this.writer = nextWriter;
- this.hdfs_out = nextHdfsOut;
- int oldNumEntries = this.numEntries.get();
- this.numEntries.set(0);
- final String newPathString = (null == newPath ? null : FSUtils.getPath(newPath));
- if (oldPath != null) {
- this.byWalRegionSequenceIds.put(oldPath, this.sequenceIdAccounting.resetHighest());
- long oldFileLen = this.fs.getFileStatus(oldPath).getLen();
- this.totalLogSize.addAndGet(oldFileLen);
- LOG.info("Rolled WAL " + FSUtils.getPath(oldPath) + " with entries=" + oldNumEntries +
- ", filesize=" + StringUtils.byteDesc(oldFileLen) + "; new WAL " +
- newPathString);
+ if (nextWriter != null && nextWriter instanceof ProtobufLogWriter) {
+ this.hdfs_out = ((ProtobufLogWriter) nextWriter).getStream();
} else {
- LOG.info("New WAL " + newPathString);
+ this.hdfs_out = null;
}
} catch (InterruptedException ie) {
// Perpetuate the interrupt
@@ -880,223 +380,84 @@ public class FSHLog implements WAL {
LOG.error("Failed close of WAL writer " + oldPath + ", unflushedEntries=" + count, e);
throw new FailedLogCloseException(oldPath + ", unflushedEntries=" + count, e);
} finally {
- try {
- // Let the writer thread go regardless, whether error or not.
- if (zigzagLatch != null) {
- zigzagLatch.releaseSafePoint();
- // syncFuture will be null if we failed our wait on safe point above. Otherwise, if
- // latch was obtained successfully, the sync we threw in either trigger the latch or it
- // got stamped with an exception because the WAL was damaged and we could not sync. Now
- // the write pipeline has been opened up again by releasing the safe point, process the
- // syncFuture we got above. This is probably a noop but it may be stale exception from
- // when old WAL was in place. Catch it if so.
- if (syncFuture != null) {
- try {
- blockOnSync(syncFuture);
- } catch (IOException ioe) {
- if (LOG.isTraceEnabled()) LOG.trace("Stale sync exception", ioe);
+ // Let the writer thread go regardless, whether error or not.
+ if (zigzagLatch != null) {
+ zigzagLatch.releaseSafePoint();
+ // syncFuture will be null if we failed our wait on safe point above. Otherwise, if
+ // latch was obtained successfully, the sync we threw in either trigger the latch or it
+ // got stamped with an exception because the WAL was damaged and we could not sync. Now
+ // the write pipeline has been opened up again by releasing the safe point, process the
+ // syncFuture we got above. This is probably a noop but it may be stale exception from
+ // when old WAL was in place. Catch it if so.
+ if (syncFuture != null) {
+ try {
+ blockOnSync(syncFuture);
+ } catch (IOException ioe) {
+ if (LOG.isTraceEnabled()) {
+ LOG.trace("Stale sync exception", ioe);
}
}
}
- } finally {
- scope.close();
}
}
- return newPath;
- }
-
- long getUnflushedEntriesCount() {
- long highestSynced = this.highestSyncedSequence.get();
- return highestSynced > this.highestUnsyncedSequence?
- 0: this.highestUnsyncedSequence - highestSynced;
- }
-
- boolean isUnflushedEntries() {
- return getUnflushedEntriesCount() > 0;
+ return oldFileLen;
}
- /*
- * only public so WALSplitter can use.
- * @return archived location of a WAL file with the given path p
- */
- public static Path getWALArchivePath(Path archiveDir, Path p) {
- return new Path(archiveDir, p.getName());
- }
-
- private void archiveLogFile(final Path p) throws IOException {
- Path newPath = getWALArchivePath(this.fullPathArchiveDir, p);
- // Tell our listeners that a log is going to be archived.
- if (!this.listeners.isEmpty()) {
- for (WALActionsListener i : this.listeners) {
- i.preLogArchive(p, newPath);
- }
- }
- LOG.info("Archiving " + p + " to " + newPath);
- if (!FSUtils.renameAndSetModifyTime(this.fs, p, newPath)) {
- throw new IOException("Unable to rename " + p + " to " + newPath);
- }
- // Tell our listeners that a log has been archived.
- if (!this.listeners.isEmpty()) {
- for (WALActionsListener i : this.listeners) {
- i.postLogArchive(p, newPath);
+ @Override
+ protected void doShutdown() throws IOException {
+ // Shutdown the disruptor. Will stop after all entries have been processed. Make sure we
+ // have stopped incoming appends before calling this else it will not shutdown. We are
+ // conservative below waiting a long time and if not elapsed, then halting.
+ if (this.disruptor != null) {
+ long timeoutms = conf.getLong("hbase.wal.disruptor.shutdown.timeout.ms", 60000);
+ try {
+ this.disruptor.shutdown(timeoutms, TimeUnit.MILLISECONDS);
+ } catch (TimeoutException e) {
+ LOG.warn("Timed out bringing down disruptor after " + timeoutms + "ms; forcing halt "
+ + "(It is a problem if this is NOT an ABORT! -- DATALOSS!!!!)");
+ this.disruptor.halt();
+ this.disruptor.shutdown();
}
}
- }
-
- /**
- * This is a convenience method that computes a new filename with a given
- * file-number.
- * @param filenum to use
- * @return Path
- */
- protected Path computeFilename(final long filenum) {
- if (filenum < 0) {
- throw new RuntimeException("WAL file number can't be < 0");
+ // With disruptor down, this is safe to let go.
+ if (this.appendExecutor != null) {
+ this.appendExecutor.shutdown();
}
- String child = logFilePrefix + WAL_FILE_NAME_DELIMITER + filenum + logFileSuffix;
- return new Path(fullPathLogDir, child);
- }
-
- /**
- * This is a convenience method that computes a new filename with a given
- * using the current WAL file-number
- * @return Path
- */
- public Path getCurrentFileName() {
- return computeFilename(this.filenum.get());
- }
-
- @Override
- public String toString() {
- return "FSHLog " + logFilePrefix + ":" + logFileSuffix + "(num " + filenum + ")";
- }
-/**
- * A log file has a creation timestamp (in ms) in its file name ({@link #filenum}.
- * This helper method returns the creation timestamp from a given log file.
- * It extracts the timestamp assuming the filename is created with the
- * {@link #computeFilename(long filenum)} method.
- * @param fileName
- * @return timestamp, as in the log file name.
- */
- protected long getFileNumFromFileName(Path fileName) {
- if (fileName == null) throw new IllegalArgumentException("file name can't be null");
- if (!ourFiles.accept(fileName)) {
- throw new IllegalArgumentException("The log file " + fileName +
- " doesn't belong to this WAL. (" + toString() + ")");
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Closing WAL writer in " + FSUtils.getPath(walDir));
}
- final String fileNameString = fileName.toString();
- String chompedPath = fileNameString.substring(prefixPathStr.length(),
- (fileNameString.length() - logFileSuffix.length()));
- return Long.parseLong(chompedPath);
- }
-
- @Override
- public void close() throws IOException {
- shutdown();
- final FileStatus[] files = getFiles();
- if (null != files && 0 != files.length) {
- for (FileStatus file : files) {
- Path p = getWALArchivePath(this.fullPathArchiveDir, file.getPath());
- // Tell our listeners that a log is going to be archived.
- if (!this.listeners.isEmpty()) {
- for (WALActionsListener i : this.listeners) {
- i.preLogArchive(file.getPath(), p);
- }
- }
-
- if (!FSUtils.renameAndSetModifyTime(fs, file.getPath(), p)) {
- throw new IOException("Unable to rename " + file.getPath() + " to " + p);
- }
- // Tell our listeners that a log was archived.
- if (!this.listeners.isEmpty()) {
- for (WALActionsListener i : this.listeners) {
- i.postLogArchive(file.getPath(), p);
- }
- }
- }
- LOG.debug("Moved " + files.length + " WAL file(s) to " +
- FSUtils.getPath(this.fullPathArchiveDir));
+ if (this.writer != null) {
+ this.writer.close();
+ this.writer = null;
}
- LOG.info("Closed WAL: " + toString());
}
@Override
- public void shutdown() throws IOException {
- if (shutdown.compareAndSet(false, true)) {
- try {
- // Prevent all further flushing and rolling.
- closeBarrier.stopAndDrainOps();
- } catch (InterruptedException e) {
- LOG.error("Exception while waiting for cache flushes and log rolls", e);
- Thread.currentThread().interrupt();
- }
-
- // Shutdown the disruptor. Will stop after all entries have been processed. Make sure we
- // have stopped incoming appends before calling this else it will not shutdown. We are
- // conservative below waiting a long time and if not elapsed, then halting.
- if (this.disruptor != null) {
- long timeoutms = conf.getLong("hbase.wal.disruptor.shutdown.timeout.ms", 60000);
- try {
- this.disruptor.shutdown(timeoutms, TimeUnit.MILLISECONDS);
- } catch (TimeoutException e) {
- LOG.warn("Timed out bringing down disruptor after " + timeoutms + "ms; forcing halt " +
- "(It is a problem if this is NOT an ABORT! -- DATALOSS!!!!)");
- this.disruptor.halt();
- this.disruptor.shutdown();
- }
- }
- // With disruptor down, this is safe to let go.
- if (this.appendExecutor != null) this.appendExecutor.shutdown();
-
- // Tell our listeners that the log is closing
- if (!this.listeners.isEmpty()) {
- for (WALActionsListener i : this.listeners) {
- i.logCloseRequested();
- }
- }
- this.closed = true;
- if (LOG.isDebugEnabled()) {
- LOG.debug("Closing WAL writer in " + FSUtils.getPath(fullPathLogDir));
- }
- if (this.writer != null) {
- this.writer.close();
- this.writer = null;
- }
- }
+ public String toString() {
+ return "FSHLog " + walFilePrefix + ":" + walFileSuffix + "(num " + filenum + ")";
}
- /**
- * NOTE: This append, at a time that is usually after this call returns, starts an
- * mvcc transaction by calling 'begin' wherein which we assign this update a sequenceid. At
- * assignment time, we stamp all the passed in Cells inside WALEdit with their sequenceId.
- * You must 'complete' the transaction this mvcc transaction by calling
- * MultiVersionConcurrencyControl#complete(...) or a variant otherwise mvcc will get stuck. Do it
- * in the finally of a try/finally
- * block within which this append lives and any subsequent operations like sync or
- * update of memstore, etc. Get the WriteEntry to pass mvcc out of the passed in WALKey
- * <code>walKey</code> parameter. Be warned that the WriteEntry is not immediately available
- * on return from this method. It WILL be available subsequent to a sync of this append;
- * otherwise, you will just have to wait on the WriteEntry to get filled in.
- */
- @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="NP_NULL_ON_SOME_PATH_EXCEPTION",
- justification="Will never be null")
+ @edu.umd.cs.findbugs.annotations.SuppressWarnings(value = "NP_NULL_ON_SOME_PATH_EXCEPTION",
+ justification = "Will never be null")
@Override
public long append(final HRegionInfo hri,
final WALKey key, final WALEdit edits, final boolean inMemstore) throws IOException {
- if (this.closed) throw new IOException("Cannot append; log is closed");
- // Make a trace scope for the append. It is closed on other side of the ring buffer by the
- // single consuming thread. Don't have to worry about it.
+ if (this.closed) {
+ throw new IOException("Cannot append; log is closed");
+ }
+ // Make a trace scope for the append. It is closed on other side of the ring buffer by the
+ // single consuming thread. Don't have to worry about it.
TraceScope scope = Trace.startSpan("FSHLog.append");
- // This is crazy how much it takes to make an edit. Do we need all this stuff!!!!???? We need
+ // This is crazy how much it takes to make an edit. Do we need all this stuff!!!!???? We need
// all this to make a key and then below to append the edit, we need to carry htd, info,
// etc. all over the ring buffer.
FSWALEntry entry = null;
long sequence = this.disruptor.getRingBuffer().next();
try {
RingBufferTruck truck = this.disruptor.getRingBuffer().get(sequence);
- // Construction of FSWALEntry sets a latch. The latch is thrown just after we stamp the
+ // Construction of FSWALEntry sets a latch. The latch is thrown just after we stamp the
// edit with its edit/sequence id.
// TODO: reuse FSWALEntry as we do SyncFuture rather create per append.
entry = new FSWALEntry(sequence, key, edits, hri, inMemstore);
@@ -1108,17 +469,18 @@ public class FSHLog implements WAL {
}
/**
- * Thread to runs the hdfs sync call. This call takes a while to complete. This is the longest
- * pole adding edits to the WAL and this must complete to be sure all edits persisted. We run
- * multiple threads sync'ng rather than one that just syncs in series so we have better
- * latencies; otherwise, an edit that arrived just after a sync started, might have to wait
- * almost the length of two sync invocations before it is marked done.
- * <p>When the sync completes, it marks all the passed in futures done. On the other end of the
- * sync future is a blocked thread, usually a regionserver Handler. There may be more than one
- * future passed in the case where a few threads arrive at about the same time and all invoke
- * 'sync'. In this case we'll batch up the invocations and run one filesystem sync only for a
- * batch of Handler sync invocations. Do not confuse these Handler SyncFutures with the futures
- * an ExecutorService returns when you call submit. We have no use for these in this model. These
+ * Thread to runs the hdfs sync call. This call takes a while to complete. This is the longest
+ * pole adding edits to the WAL and this must complete to be sure all edits persisted. We run
+ * multiple threads sync'ng rather than one that just syncs in series so we have better latencies;
+ * otherwise, an edit that arrived just after a sync started, might have to wait almost the length
+ * of two sync invocations before it is marked done.
+ * <p>
+ * When the sync completes, it marks all the passed in futures done. On the other end of the sync
+ * future is a blocked thread, usually a regionserver Handler. There may be more than one future
+ * passed in the case where a few threads arrive at about the same time and all invoke 'sync'. In
+ * this case we'll batch up the invocations and run one filesystem sync only for a batch of
+ * Handler sync invocations. Do not confuse these Handler SyncFutures with the futures an
+ * ExecutorService returns when you call submit. We have no use for these in this model. These
* SyncFutures are 'artificial', something to hold the Handler until the filesystem sync
* completes.
*/
@@ -1130,12 +492,13 @@ public class FSHLog implements WAL {
/**
* UPDATE!
* @param syncs the batch of calls to sync that arrived as this thread was starting; when done,
- * we will put the result of the actual hdfs sync call as the result.
- * @param sequence The sequence number on the ring buffer when this thread was set running.
- * If this actual writer sync completes then all appends up this point have been
- * flushed/synced/pushed to datanodes. If we fail, then the passed in <code>syncs</code>
- * futures will return the exception to their clients; some of the edits may have made it out
- * to data nodes but we will report all that were part of this session as failed.
+ * we will put the result of the actual hdfs sync call as the result.
+ * @param sequence The sequence number on the ring buffer when this thread was set running. If
+ * this actual writer sync completes then all appends up this point have been
+ * flushed/synced/pushed to datanodes. If we fail, then the passed in
+ * <code>syncs</code> futures will return the exception to their clients; some of the
+ * edits may have made it out to data nodes but we will report all that were part of
+ * this session as failed.
*/
SyncRunner(final String name, final int maxHandlersCount) {
super(name);
@@ -1145,17 +508,17 @@ public class FSHLog implements WAL {
//
// We could let the capacity be 'open' but bound it so we get alerted in pathological case
// where we cannot sync and we have a bunch of threads all backed up waiting on their syncs
- // to come in. LinkedBlockingQueue actually shrinks when you remove elements so Q should
- // stay neat and tidy in usual case. Let the max size be three times the maximum handlers.
+ // to come in. LinkedBlockingQueue actually shrinks when you remove elements so Q should
+ // stay neat and tidy in usual case. Let the max size be three times the maximum handlers.
// The passed in maxHandlerCount is the user-level handlers which is what we put up most of
// but HBase has other handlers running too -- opening region handlers which want to write
- // the meta table when succesful (i.e. sync), closing handlers -- etc. These are usually
+ // the meta table when succesful (i.e. sync), closing handlers -- etc. These are usually
// much fewer in number than the user-space handlers so Q-size should be user handlers plus
- // some space for these other handlers. Lets multiply by 3 for good-measure.
+ // some space for these other handlers. Lets multiply by 3 for good-measure.
this.syncFutures = new LinkedBlockingQueue<SyncFuture>(maxHandlersCount * 3);
}
- void offer(final long sequence, final SyncFuture [] syncFutures, final int syncFutureCount) {
+ void offer(final long sequence, final SyncFuture[] syncFutures, final int syncFutureCount) {
// Set sequence first because the add to the queue will wake the thread if sleeping.
this.sequence = sequence;
for (int i = 0; i < syncFutureCount; ++i) {
@@ -1165,28 +528,28 @@ public class FSHLog implements WAL {
/**
* Release the passed <code>syncFuture</code>
- * @param syncFuture
- * @param currentSequence
- * @param t
* @return Returns 1.
*/
private int releaseSyncFuture(final SyncFuture syncFuture, final long currentSequence,
final Throwable t) {
- if (!syncFuture.done(currentSequence, t)) throw new IllegalStateException();
+ if (!syncFuture.done(currentSequence, t)) {
+ throw new IllegalStateException();
+ }
// This function releases one sync future only.
return 1;
}
/**
* Release all SyncFutures whose sequence is <= <code>currentSequence</code>.
- * @param currentSequence
* @param t May be non-null if we are processing SyncFutures because an exception was thrown.
* @return Count of SyncFutures we let go.
*/
private int releaseSyncFutures(final long currentSequence, final Throwable t) {
int syncCount = 0;
for (SyncFuture syncFuture; (syncFuture = this.syncFutures.peek()) != null;) {
- if (syncFuture.getRingBufferSequence() > currentSequence) break;
+ if (syncFuture.getTxid() > currentSequence) {
+ break;
+ }
releaseSyncFuture(syncFuture, currentSequence, t);
if (!this.syncFutures.remove(syncFuture)) {
throw new IllegalStateException(syncFuture.toString());
@@ -1204,14 +567,14 @@ public class FSHLog implements WAL {
long currentHighestSyncedSequence;
// Set the highestSyncedSequence IFF our current sequence id is the 'highest'.
do {
- currentHighestSyncedSequence = highestSyncedSequence.get();
+ currentHighestSyncedSequence = highestSyncedTxid.get();
if (currentHighestSyncedSequence >= sequence) {
// Set the sync number to current highwater mark; might be able to let go more
// queued sync futures
sequence = currentHighestSyncedSequence;
break;
}
- } while (!highestSyncedSequence.compareAndSet(currentHighestSyncedSequence, sequence));
+ } while (!highestSyncedTxid.compareAndSet(currentHighestSyncedSequence, sequence));
return sequence;
}
@@ -1225,21 +588,21 @@ public class FSHLog implements WAL {
// We have to process what we 'take' from the queue
takeSyncFuture = this.syncFutures.take();
currentSequence = this.sequence;
- long syncFutureSequence = takeSyncFuture.getRingBufferSequence();
+ long syncFutureSequence = takeSyncFuture.getTxid();
if (syncFutureSequence > currentSequence) {
- throw new IllegalStateException("currentSequence=" + syncFutureSequence +
- ", syncFutureSequence=" + syncFutureSequence);
+ throw new IllegalStateException("currentSequence=" + syncFutureSequence
+ + ", syncFutureSequence=" + syncFutureSequence);
}
// See if we can process any syncfutures BEFORE we go sync.
- long currentHighestSyncedSequence = highestSyncedSequence.get();
+ long currentHighestSyncedSequence = highestSyncedTxid.get();
if (currentSequence < currentHighestSyncedSequence) {
syncCount += releaseSyncFuture(takeSyncFuture, currentHighestSyncedSequence, null);
- // Done with the 'take'. Go around again and do a new 'take'.
+ // Done with the 'take'. Go around again and do a new 'take'.
continue;
}
break;
}
- // I got something. Lets run. Save off current sequence number in case it changes
+ // I got something. Lets run. Save off current sequence number in case it changes
// while we run.
TraceScope scope = Trace.continueSpan(takeSyncFuture.getSpan());
long start = System.nanoTime();
@@ -1262,8 +625,11 @@ public class FSHLog implements WAL {
syncCount += releaseSyncFuture(takeSyncFuture, currentSequence, lastException);
// Can we release other syncs?
syncCount += releaseSyncFutures(currentSequence, lastException);
- if (lastException != null) requestLogRoll();
- else checkLogRoll();
+ if (lastException != null) {
+ requestLogRoll();
+ } else {
+ checkLogRoll();
+ }
}
postSync(System.nanoTime() - start, syncCount);
} catch (InterruptedException e) {
@@ -1281,7 +647,9 @@ public class FSHLog implements WAL {
*/
void checkLogRoll() {
// Will return immediately if we are in the middle of a WAL log roll currently.
- if (!rollWriterLock.tryLock()) return;
+ if (!rollWriterLock.tryLock()) {
+ return;
+ }
boolean lowReplication;
try {
lowReplication = checkLowReplication();
@@ -1297,7 +665,7 @@ public class FSHLog implements WAL {
}
}
- /*
+ /**
* @return true if number of replicas for the WAL is lower than threshold
*/
private boolean checkLowReplication() {
@@ -1309,11 +677,10 @@ public class FSHLog implements WAL {
if (numCurrentReplicas != 0 && numCurrentReplicas < this.minTolerableReplication) {
if (this.lowReplicationRollEnabled) {
if (this.consecutiveLogRolls.get() < this.lowReplicationRollLimit) {
- LOG.warn("HDFS pipeline error detected. " + "Found "
- + numCurrentReplicas + " replicas but expecting no less than "
- + this.minTolerableReplication + " replicas. "
- + " Requesting close of WAL. current pipeline: "
- + Arrays.toString(getPipeLine()));
+ LOG.warn("HDFS pipeline error detected. " + "Found " + numCurrentReplicas
+ + " replicas but expecting no less than " + this.minTolerableReplication
+ + " replicas. " + " Requesting close of WAL. current pipeline: "
+ + Arrays.toString(getPipeline()));
logRollNeeded = true;
// If rollWriter is requested, increase consecutiveLogRolls. Once it
// is larger than lowReplicationRollLimit, disable the
@@ -1341,8 +708,7 @@ public class FSHLog implements WAL {
}
}
} catch (Exception e) {
- LOG.warn("DFSOutputStream.getNumCurrentReplicas failed because of " + e +
- ", continuing...");
+ LOG.warn("DFSOutputStream.getNumCurrentReplicas failed because of " + e + ", continuing...");
}
return logRollNeeded;
}
@@ -1353,6 +719,7 @@ public class FSHLog implements WAL {
private SyncFuture publishSyncOnRingBuffer(Span span) {
long sequence = this.disruptor.getRingBuffer().next();
+ // here we use ring buffer sequence as transaction id
SyncFuture syncFuture = getSyncFuture(sequence, span);
try {
RingBufferTruck truck = this.disruptor.getRingBuffer().get(sequence);
@@ -1368,81 +735,17 @@ public class FSHLog implements WAL {
return blockOnSync(publishSyncOnRingBuffer(span));
}
- private Span blockOnSync(final SyncFuture syncFuture) throws IOException {
- // Now we have published the ringbuffer, halt the current thread until we get an answer back.
- try {
- syncFuture.get();
- return syncFuture.getSpan();
- } catch (InterruptedException ie) {
- LOG.warn("Interrupted", ie);
- throw convertInterruptedExceptionToIOException(ie);
- } catch (ExecutionException e) {
- throw ensureIOException(e.getCause());
- }
- }
-
- private IOException convertInterruptedExceptionToIOException(final InterruptedException ie) {
- Thread.currentThread().interrupt();
- IOException ioe = new InterruptedIOException();
- ioe.initCause(ie);
- return ioe;
- }
-
- private SyncFuture getSyncFuture(final long sequence, Span span) {
- SyncFuture syncFuture = this.syncFuturesByHandler.get(Thread.currentThread());
- if (syncFuture == null) {
- syncFuture = new SyncFuture();
- this.syncFuturesByHandler.put(Thread.currentThread(), syncFuture);
- }
- return syncFuture.reset(sequence, span);
- }
-
- private void postSync(final long timeInNanos, final int handlerSyncs) {
- if (timeInNanos > this.slowSyncNs) {
- String msg =
- new StringBuilder().append("Slow sync cost: ")
- .append(timeInNanos / 1000000).append(" ms, current pipeline: ")
- .append(Arrays.toString(getPipeLine())).toString();
- Trace.addTimelineAnnotation(msg);
- LOG.info(msg);
- }
- if (!listeners.isEmpty()) {
- for (WALActionsListener listener : listeners) {
- listener.postSync(timeInNanos, handlerSyncs);
- }
- }
- }
-
- private long postAppend(final Entry e, final long elapsedTime) {
- long len = 0;
- if (!listeners.isEmpty()) {
- for (Cell cell : e.getEdit().getCells()) {
- len += CellUtil.estimatedSerializedSizeOf(cell);
- }
- for (WALActionsListener listener : listeners) {
- listener.postAppend(len, elapsedTime);
- }
- }
- return len;
- }
-
-
/**
- * This method gets the datanode replication count for the current WAL.
- *
- * If the pipeline isn't started yet or is empty, you will get the default
- * replication factor. Therefore, if this function returns 0, it means you
- * are not properly running with the HDFS-826 patch.
- * @throws InvocationTargetException
- * @throws IllegalAccessException
- * @throws IllegalArgumentException
- *
- * @throws Exception
+ * {@inheritDoc}
+ * <p>
+ * If the pipeline isn't started yet or is empty, you will get the default replication factor.
+ * Therefore, if this function returns 0, it means you are not properly running with the HDFS-826
+ * patch.
*/
@VisibleForTesting
int getLogReplication() {
try {
- //in standalone mode, it will return 0
+ // in standalone mode, it will return 0
if (this.hdfs_out instanceof HdfsDataOutputStream) {
return ((HdfsDataOutputStream) this.hdfs_out).getCurrentBlockReplication();
}
@@ -1465,7 +768,7 @@ public class FSHLog implements WAL {
@Override
public void sync(long txid) throws IOException {
- if (this.highestSyncedSequence.get() >= txid){
+ if (this.highestSyncedTxid.get() >= txid) {
// Already sync'd.
return;
}
@@ -1478,70 +781,20 @@ public class FSHLog implements WAL {
}
}
- // public only until class moves to o.a.h.h.wal
- public void requestLogRoll() {
- requestLogRoll(false);
- }
-
- private void requestLogRoll(boolean tooFewReplicas) {
- if (!this.listeners.isEmpty()) {
- for (WALActionsListener i: this.listeners) {
- i.logRollRequested(tooFewReplicas);
- }
- }
- }
-
- // public only until class moves to o.a.h.h.wal
- /** @return the number of rolled log files */
- public int getNumRolledLogFiles() {
- return byWalRegionSequenceIds.size();
- }
-
- // public only until class moves to o.a.h.h.wal
- /** @return the number of log files in use */
- public int getNumLogFiles() {
- // +1 for current use log
- return getNumRolledLogFiles() + 1;
- }
-
- // public only until class moves to o.a.h.h.wal
- /** @return the size of log files in use */
- public long getLogFileSize() {
- return this.totalLogSize.get();
- }
-
- @Override
- public Long startCacheFlush(final byte[] encodedRegionName, Set<byte[]> families) {
- if (!closeBarrier.beginOp()) {
- LOG.info("Flush not started for " + Bytes.toString(encodedRegionName) + "; server closing.");
- return null;
- }
- return this.sequenceIdAccounting.startCacheFlush(encodedRegionName, families);
- }
-
- @Override
- public void completeCacheFlush(final byte [] encodedRegionName) {
- this.sequenceIdAccounting.completeCacheFlush(encodedRegionName);
- closeBarrier.endOp();
- }
-
@Override
- public void abortCacheFlush(byte[] encodedRegionName) {
- this.sequenceIdAccounting.abortCacheFlush(encodedRegionName);
- closeBarrier.endOp();
+ public void logRollerExited() {
}
@VisibleForTesting
boolean isLowReplicationRollEnabled() {
- return lowReplicationRollEnabled;
+ return lowReplicationRollEnabled;
}
- public static final long FIXED_OVERHEAD = ClassSize.align(
- ClassSize.OBJECT + (5 * ClassSize.REFERENCE) +
- ClassSize.ATOMIC_INTEGER + Bytes.SIZEOF_INT + (3 * Bytes.SIZEOF_LONG));
+ public static final long FIXED_OVERHEAD = ClassSize
+ .align(ClassSize.OBJECT + (5 * ClassSize.REFERENCE) + ClassSize.ATOMIC_INTEGER
+ + Bytes.SIZEOF_INT + (3 * Bytes.SIZEOF_LONG));
- private static void split(final Configuration conf, final Path p)
- throws IOException {
+ private static void split(final Configuration conf, final Path p) throws IOException {
FileSystem fs = FileSystem.get(conf);
if (!fs.exists(p)) {
throw new FileNotFoundException(p.toString());
@@ -1555,51 +808,30 @@ public class FSHLog implements WAL {
WALSplitter.split(baseDir, p, archiveDir, fs, conf, WALFactory.getInstance(conf));
}
-
- @Override
- public long getEarliestMemstoreSeqNum(byte[] encodedRegionName) {
- // Used by tests. Deprecated as too subtle for general usage.
- return this.sequenceIdAccounting.getLowestSequenceId(encodedRegionName);
- }
-
- @Override
- public long getEarliestMemstoreSeqNum(byte[] encodedRegionName, byte[] familyName) {
- // This method is used by tests and for figuring if we should flush or not because our
- // sequenceids are too old. It is also used reporting the master our oldest sequenceid for use
- // figuring what edits can be skipped during log recovery. getEarliestMemStoreSequenceId
- // from this.sequenceIdAccounting is looking first in flushingOldestStoreSequenceIds, the
- // currently flushing sequence ids, and if anything found there, it is returning these. This is
- // the right thing to do for the reporting oldest sequenceids to master; we won't skip edits if
- // we crash during the flush. For figuring what to flush, we might get requeued if our sequence
- // id is old even though we are currently flushing. This may mean we do too much flushing.
- return this.sequenceIdAccounting.getLowestSequenceId(encodedRegionName, familyName);
- }
-
/**
- * This class is used coordinating two threads holding one thread at a
- * 'safe point' while the orchestrating thread does some work that requires the first thread
- * paused: e.g. holding the WAL writer while its WAL is swapped out from under it by another
- * thread.
- *
- * <p>Thread A signals Thread B to hold when it gets to a 'safe point'. Thread A wait until
- * Thread B gets there. When the 'safe point' has been attained, Thread B signals Thread A.
- * Thread B then holds at the 'safe point'. Thread A on notification that Thread B is paused,
- * goes ahead and does the work it needs to do while Thread B is holding. When Thread A is done,
- * it flags B and then Thread A and Thread B continue along on their merry way. Pause and
- * signalling 'zigzags' between the two participating threads. We use two latches -- one the
- * inverse of the other -- pausing and signaling when states are achieved.
- *
- * <p>To start up the drama, Thread A creates an instance of this class each time it would do
- * this zigzag dance and passes it to Thread B (these classes use Latches so it is one shot
- * only). Thread B notices the new instance (via reading a volatile reference or how ever) and it
- * starts to work toward the 'safe point'. Thread A calls {@link #waitSafePoint()} when it
- * cannot proceed until the Thread B 'safe point' is attained. Thread A will be held inside in
- * {@link #waitSafePoint()} until Thread B reaches the 'safe point'. Once there, Thread B
- * frees Thread A by calling {@link #safePointAttained()}. Thread A now knows Thread B
- * is at the 'safe point' and that it is holding there (When Thread B calls
- * {@link #safePointAttained()} it blocks here until Thread A calls {@link #releaseSafePoint()}).
- * Thread A proceeds to do what it needs to do while Thread B is paused. When finished,
- * it lets Thread B lose by calling {@link #releaseSafePoint()} and away go both Threads again.
+ * This class is used coordinating two threads holding one thread at a 'safe point' while the
+ * orchestrating thread does some work that requires the first thread paused: e.g. holding the WAL
+ * writer while its WAL is swapped out from under it by another thread.
+ * <p>
+ * Thread A signals Thread B to hold when it gets to a 'safe point'. Thread A wait until Thread B
+ * gets there. When the 'safe point' has been attained, Thread B signals Thread A. Thread B then
+ * holds at the 'safe point'. Thread A on notification that Thread B is paused, goes ahead and
+ * does the work it needs to do while Thread B is holding. When Thread A is done, it flags B and
+ * then Thread A and Thread B continue along on their merry way. Pause and signalling 'zigzags'
+ * between the two participating threads. We use two latches -- one the inverse of the other --
+ * pausing and signaling when states are achieved.
+ * <p>
+ * To start up the drama, Thread A creates an instance of this class each time it would do this
+ * zigzag dance and passes it to Thread B (these classes use Latches so it is one shot only).
+ * Thread B notices the new instance (via reading a volatile reference or how ever) and it starts
+ * to work toward the 'safe point'. Thread A calls {@link #waitSafePoint()} when it cannot proceed
+ * until the Thread B 'safe point' is attained. Thread A will be held inside in
+ * {@link #waitSafePoint()} until Thread B reaches the 'safe point'. Once there, Thread B frees
+ * Thread A by calling {@link #safePointAttained()}. Thread A now knows Thread B is at the 'safe
+ * point' and that it is holding there (When Thread B calls {@link #safePointAttained()} it blocks
+ * here until Thread A calls {@link #releaseSafePoint()}). Thread A proceeds to do what it needs
+ * to do while Thread B is paused. When finished, it lets Thread B lose by calling
+ * {@link #releaseSafePoint()} and away go both Threads again.
*/
static class SafePointZigZagLatch {
/**
@@ -1607,24 +839,23 @@ public class FSHLog implements WAL {
*/
private volatile CountDownLatch safePointAttainedLatch = new CountDownLatch(1);
/**
- * Latch to wait on. Will be released when we can proceed.
+ * Latch to wait on. Will be released when we can proceed.
*/
private volatile CountDownLatch safePointReleasedLatch = new CountDownLatch(1);
/**
- * For Thread A to call when it is ready to wait on the 'safe point' to be attained.
- * Thread A will be held in here until Thread B calls {@link #safePointAttained()}
- * @param syncFuture We need this as barometer on outstanding syncs. If it comes home with
- * an exception, then something is up w/ our syncing.
- * @throws InterruptedException
- * @throws ExecutionException
+ * For Thread A to call when it is ready to wait on the 'safe point' to be attained. Thread A
+ * will be held in here until Thread B calls {@link #safePointAttained()}
+ * @param syncFuture We need this as barometer on outstanding syncs. If it comes home with an
+ * exception, then something is up w/ our syncing.
* @return The passed <code>syncFuture</code>
- * @throws FailedSyncBeforeLogCloseException
*/
- SyncFuture waitSafePoint(final SyncFuture syncFuture)
- throws InterruptedException, FailedSyncBeforeLogCloseException {
+ SyncFuture waitSafePoint(final SyncFuture syncFuture) throws InterruptedException,
+ FailedSyncBeforeLogCloseException {
while (true) {
- if (this.safePointAttainedLatch.await(1, TimeUnit.NANOSECONDS)) break;
+ if (this.safePointAttainedLatch.await(1, TimeUnit.NANOSECONDS)) {
+ break;
+ }
if (syncFuture.isThrowable()) {
throw new FailedSyncBeforeLogCloseException(syncFuture.getThrowable());
}
@@ -1633,10 +864,9 @@ public class FSHLog implements WAL {
}
/**
- * Called by Thread B when it attains the 'safe point'. In this method, Thread B signals
- * Thread A it can proceed. Thread B will be held in here until {@link #releaseSafePoint()}
- * is called by Thread A.
- * @throws InterruptedException
+ * Called by Thread B when it attains the 'safe point'. In this method, Thread B signals Thread
+ * A it can proceed. Thread B will be held in here until {@link #releaseSafePoint()} is called
+ * by Thread A.
*/
void safePointAttained() throws InterruptedException {
this.safePointAttainedLatch.countDown();
@@ -1644,8 +874,8 @@ public class FSHLog implements WAL {
}
/**
- * Called by Thread A when it is done with the work it needs to do while Thread B is
- * halted. This will release the Thread B held in a call to {@link #safePointAttained()}
+ * Called by Thread A when it is done with the work it needs to do while Thread B is halted.
+ * This will release the Thread B held in a call to {@link #safePointAttained()}
*/
void releaseSafePoint() {
this.safePointReleasedLatch.countDown();
@@ -1655,44 +885,44 @@ public class FSHLog implements WAL {
* @return True is this is a 'cocked', fresh instance, and not one that has already fired.
*/
boolean isCocked() {
- return this.safePointAttainedLatch.getCount() > 0 &&
- this.safePointReleasedLatch.getCount() > 0;
+ return this.safePointAttainedLatch.getCount() > 0
+ && this.safePointReleasedLatch.getCount() > 0;
}
}
/**
* Handler that is run by the disruptor ringbuffer consumer. Consumer is a SINGLE
- * 'writer/appender' thread. Appends edits and starts up sync runs. Tries its best to batch up
- * syncs. There is no discernible benefit batching appends so we just append as they come in
- * because it simplifies the below implementation. See metrics for batching effectiveness
- * (In measurement, at 100 concurrent handlers writing 1k, we are batching > 10 appends and 10
- * handler sync invocations for every actual dfsclient sync call; at 10 concurrent handlers,
- * YMMV).
- * <p>Herein, we have an array into which we store the sync futures as they come in. When we
- * have a 'batch', we'll then pass what we have collected to a SyncRunner thread to do the
- * filesystem sync. When it completes, it will then call
- * {@link SyncFuture#done(long, Throwable)} on each of SyncFutures in the batch to release
- * blocked Handler threads.
- * <p>I've tried various effects to try and make latencies low while keeping throughput high.
- * I've tried keeping a single Queue of SyncFutures in this class appending to its tail as the
- * syncs coming and having sync runner threads poll off the head to 'finish' completed
- * SyncFutures. I've tried linkedlist, and various from concurrent utils whether
- * LinkedBlockingQueue or ArrayBlockingQueue, etc. The more points of synchronization, the
- * more 'work' (according to 'perf stats') that has to be done; small increases in stall
- * percentages seem to have a big impact on throughput/latencies. The below model where we have
- * an array into which we stash the syncs and then hand them off to the sync thread seemed like
- * a decent compromise. See HBASE-8755 for more detail.
+ * 'writer/appender' thread. Appends edits and starts up sync runs. Tries its best to batch up
+ * syncs. There is no discernible benefit batching appends so we just append as they come in
+ * because it simplifies the below implementation. See metrics for batching effectiveness (In
+ * measurement, at 100 concurrent handlers writing 1k, we are batching > 10 appends and 10 handler
+ * sync invocations for every actual dfsclient sync call; at 10 concurrent handlers, YMMV).
+ * <p>
+ * Herein, we have an array into which we store the sync futures as they come in. When we have a
+ * 'batch', we'll then pass what we have collected to a SyncRunner thread to do the filesystem
+ * sync. When it completes, it will then call {@link SyncFuture#done(long, Throwable)} on each of
+ * SyncFutures in the batch to release blocked Handler threads.
+ * <p>
+ * I've tried various effects to try and make latencies low while keeping throughput high. I've
+ * tried keeping a single Queue of SyncFutures in this class appending to its tail as the syncs
+ * coming and having sync runner threads poll off the head to 'finish' completed SyncFutures. I've
+ * tried linkedlist, and various from concurrent utils whether LinkedBlockingQueue or
+ * ArrayBlockingQueue, etc. The more points of synchronization, the more 'work' (according to
+ * 'perf stats') that has to be done; small increases in stall percentages seem to have a big
+ * impact on throughput/latencies. The below model where we have an array into which we stash the
+ * syncs and then hand them off to the sync thread seemed like a decent compromise. See HBASE-8755
+ * for more detail.
*/
class RingBufferEventHandler implements EventHandler<RingBufferTruck>, LifecycleAware {
- private final SyncRunner [] syncRunners;
- private final SyncFuture [] syncFutures;
- // Had 'interesting' issues when this was non-volatile. On occasion, we'd not pass all
+ private final SyncRunner[] syncRunners;
+ private final SyncFuture[] syncFutures;
+ // Had 'interesting' issues when this was non-volatile. On occasion, we'd not pass all
// syncFutures to the next sync'ing thread.
private volatile int syncFuturesCount = 0;
private volatile SafePointZigZagLatch zigzagLatch;
/**
- * Set if we get an exception appending or syncing so that all subsequence appends and syncs
- * on this WAL fail until WAL is replaced.
+ * Set if we get an exception appending or syncing so that all subsequence appends and syncs on
+ * this WAL fail until WAL is replaced.
*/
private Exception exception = null;
/**
@@ -1716,7 +946,9 @@ public class FSHLog implements WAL {
private void cleanupOutstandingSyncsOnException(final long sequence, final Exception e) {
// There could be handler-count syncFutures outstanding.
- for (int i = 0; i < this.syncFuturesCount; i++) this.syncFutures[i].done(sequence, e);
+ for (int i = 0; i < this.syncFuturesCount; i++) {
+ this.syncFutures[i].done(sequence, e);
+ }
this.syncFuturesCount = 0;
}
@@ -1725,7 +957,9 @@ public class FSHLog implements WAL {
*/
private boolean isOutstandingSyncs() {
for (int i = 0; i < this.syncFuturesCount; i++) {
- if (!this.syncFutures[i].isDone()) return true;
+ if (!this.syncFutures[i].isDone()) {
+ return true;
+ }
}
return false;
}
@@ -1733,10 +967,10 @@ public class FSHLog implements WAL {
@Override
// We can set endOfBatch in the below method if at end of our this.syncFutures array
public void onEvent(final RingBufferTruck truck, final long sequence, boolean endOfBatch)
- throws Exception {
- // Appends and syncs are coming in order off the ringbuffer. We depend on this fact. We'll
- // add appends to dfsclient as they come in. Batching appends doesn't give any significant
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