org.apache.hadoop.hbase.regionserver.wal

Class FSHLog

java.lang.Object

org.apache.hadoop.hbase.regionserver.wal.AbstractFSWAL<WALProvider.Writer>

org.apache.hadoop.hbase.regionserver.wal.FSHLog

All Implemented Interfaces:

Closeable, AutoCloseable, WALFileLengthProvider, WAL

@InterfaceAudience.Private
public class FSHLog
extends AbstractFSWAL<WALProvider.Writer>

The default implementation of FSWAL.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.wal.WAL

WAL.Entry, WAL.Reader

Field Summary

Fields

Modifier and Type	Field and Description
static long	FIXED_OVERHEAD

Fields inherited from class org.apache.hadoop.hbase.regionserver.wal.AbstractFSWAL

blocksize, closed, conf, coprocessorHost, DEFAULT_SLOW_SYNC_TIME_MS, filenum, fs, highestSyncedTxid, highestUnsyncedTxid, implClassName, listeners, logrollsize, maxLogs, numEntries, ourFiles, prefixPathStr, rollWriterLock, sequenceIdAccounting, shutdown, slowSyncNs, totalLogSize, walArchiveDir, walDir, walFile2Props, walFilePrefix, walFileSuffix

Constructor Summary

Constructors

Constructor and Description
FSHLog(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path root, String logDir, org.apache.hadoop.conf.Configuration conf) Constructor.
FSHLog(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path rootDir, String logDir, String archiveDir, org.apache.hadoop.conf.Configuration conf, List<WALActionsListener> listeners, boolean failIfWALExists, String prefix, String suffix) Create an edit log at the given dir location.

Method Summary

Modifier and Type	Method and Description
protected void	afterCreatingZigZagLatch() Used to manufacture race condition reliably.
long	append(RegionInfo hri, WALKeyImpl key, WALEdit edits, boolean inMemstore) 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.
protected void	beforeWaitOnSafePoint()
protected WALProvider.Writer	createWriterInstance(org.apache.hadoop.fs.Path path) This method allows subclasses to inject different writers without having to extend other methods like rollWriter().
protected void	doAppend(WALProvider.Writer writer, org.apache.hadoop.hbase.regionserver.wal.FSWALEntry entry)
protected boolean	doCheckLogLowReplication()
protected void	doReplaceWriter(org.apache.hadoop.fs.Path oldPath, org.apache.hadoop.fs.Path newPath, WALProvider.Writer nextWriter)
protected void	doShutdown()
protected long	getSequenceOnRingBuffer()
protected org.apache.hadoop.hbase.regionserver.wal.SyncFuture	publishSyncOnRingBuffer(long sequence, boolean forceSync)
void	sync() Sync what we have in the WAL.
void	sync(boolean forceSync)
void	sync(long txid) Sync the WAL if the txId was not already sync'd.
void	sync(long txid, boolean forceSync)

Methods inherited from class org.apache.hadoop.hbase.regionserver.wal.AbstractFSWAL

abortCacheFlush, append, atHeadOfRingBufferEventHandlerAppend, blockOnSync, checkLogLowReplication, close, completeCacheFlush, computeFilename, getCoprocessorHost, getCurrentFileName, getEarliestMemStoreSeqNum, getEarliestMemStoreSeqNum, getFilenum, getFileNumFromFileName, getLogFileSize, getLogFileSizeIfBeingWritten, getNumLogFiles, getNumRolledLogFiles, getPreallocatedEventCount, getSyncFuture, getWALArchivePath, logRollAndSetupWalProps, main, postSync, registerWALActionsListener, requestLogRoll, requestLogRoll, rollWriter, rollWriter, shutdown, stampSequenceIdAndPublishToRingBuffer, startCacheFlush, startCacheFlush, toString, unregisterWALActionsListener, updateStore

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

FIXED_OVERHEAD

public static final long FIXED_OVERHEAD

Constructor Detail

FSHLog

public FSHLog(org.apache.hadoop.fs.FileSystem fs,
              org.apache.hadoop.fs.Path root,
              String logDir,
              org.apache.hadoop.conf.Configuration conf)
       throws IOException

Constructor.

Parameters:

fs - filesystem handle

root - path for stored and archived wals

logDir - dir where wals are stored

conf - configuration to use

Throws:

IOException

FSHLog

public FSHLog(org.apache.hadoop.fs.FileSystem fs,
              org.apache.hadoop.fs.Path rootDir,
              String logDir,
              String archiveDir,
              org.apache.hadoop.conf.Configuration conf,
              List<WALActionsListener> listeners,
              boolean failIfWALExists,
              String prefix,
              String suffix)
       throws IOException

Create an edit log at the given dir 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.

Parameters:

fs - filesystem handle

rootDir - path to where logs and oldlogs

logDir - dir where wals are stored

archiveDir - dir where wals are archived

conf - configuration to use

listeners - Listeners on WAL events. Listeners passed here will be registered before we do anything else; e.g. the Constructor AbstractFSWAL.rollWriter().

failIfWALExists - If true IOException will be thrown if files related to this wal already exist.

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

suffix - will be url encoded. null is treated as empty. non-empty must start with AbstractFSWALProvider.WAL_FILE_NAME_DELIMITER

Throws:

IOException

Method Detail

createWriterInstance

protected WALProvider.Writer createWriterInstance(org.apache.hadoop.fs.Path path)
                                           throws IOException

This method allows subclasses to inject different writers without having to extend other methods like rollWriter().

Specified by:

createWriterInstance in class AbstractFSWAL<WALProvider.Writer>

Returns:

Writer instance

Throws:

IOException

afterCreatingZigZagLatch

protected void afterCreatingZigZagLatch()

Used to manufacture race condition reliably. For testing only.

See Also:

beforeWaitOnSafePoint()

beforeWaitOnSafePoint

protected void beforeWaitOnSafePoint()

See Also:

afterCreatingZigZagLatch()

doAppend

protected void doAppend(WALProvider.Writer writer,
                        org.apache.hadoop.hbase.regionserver.wal.FSWALEntry entry)
                 throws IOException

Specified by:

doAppend in class AbstractFSWAL<WALProvider.Writer>

Throws:

IOException

doReplaceWriter

protected void doReplaceWriter(org.apache.hadoop.fs.Path oldPath,
                               org.apache.hadoop.fs.Path newPath,
                               WALProvider.Writer nextWriter)
                        throws IOException

Specified by:

doReplaceWriter in class AbstractFSWAL<WALProvider.Writer>

Throws:

IOException

doShutdown

protected void doShutdown()
                   throws IOException

Specified by:

doShutdown in class AbstractFSWAL<WALProvider.Writer>

Throws:

IOException

append

public long append(RegionInfo hri,
                   WALKeyImpl key,
                   WALEdit edits,
                   boolean inMemstore)
            throws IOException

Description copied from class: AbstractFSWAL

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 walKey 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.

Specified by:

append in interface WAL

Specified by:

append in class AbstractFSWAL<WALProvider.Writer>

Parameters:

hri - the regioninfo associated with append

key - Modified by this call; we add to it this edits region edit/sequence id.

edits - Edits to append. MAY CONTAIN NO EDITS for case where we want to get an edit sequence id that is after all currently appended edits.

inMemstore - Always true except for case where we are writing a compaction completion record into the WAL; in this case the entry is just so we can finish an unfinished compaction -- it is not an edit for memstore.

Returns:

Returns a 'transaction id' and key will have the region edit/sequence id in it.

Throws:

IOException

doCheckLogLowReplication

protected boolean doCheckLogLowReplication()

Specified by:

doCheckLogLowReplication in class AbstractFSWAL<WALProvider.Writer>

Returns:

true if number of replicas for the WAL is lower than threshold

getSequenceOnRingBuffer

protected long getSequenceOnRingBuffer()

publishSyncOnRingBuffer

protected org.apache.hadoop.hbase.regionserver.wal.SyncFuture publishSyncOnRingBuffer(long sequence,
                                                                                      boolean forceSync)

sync

public void sync()
          throws IOException

Description copied from interface: WAL

Sync what we have in the WAL.

Throws:

IOException

sync

public void sync(boolean forceSync)
          throws IOException

Parameters:

forceSync - Flag to force sync rather than flushing to the buffer. Example - Hadoop hflush vs hsync.

Throws:

IOException

sync

public void sync(long txid)
          throws IOException

Description copied from interface: WAL

Sync the WAL if the txId was not already sync'd.

Parameters:

txid - Transaction id to sync to.

Throws:

IOException

sync

public void sync(long txid,
                 boolean forceSync)
          throws IOException

Parameters:

txid - Transaction id to sync to.

forceSync - Flag to force sync rather than flushing to the buffer. Example - Hadoop hflush vs hsync.

Throws:

IOException