alluxio.master.journal

Class MetadataSyncMergeJournalContext

java.lang.Object

alluxio.master.journal.FileSystemMergeJournalContext

alluxio.master.journal.MetadataSyncMergeJournalContext

All Implemented Interfaces:

JournalContext, Closeable, AutoCloseable, java.util.function.Supplier<JournalContext>

@NotThreadSafe
public class MetadataSyncMergeJournalContext
extends FileSystemMergeJournalContext

A FileSystemMergeJournalContext used in MetadataSync (InodeSyncStream). This journal context never enforces a synchronous journal flush but only appends the journals into the async journal writer. Metadata sync creates a bunch of inodes and with PropertyKey.MASTER_FILE_SYSTEM_MERGE_INODE_JOURNALS enabled, journals are committed as long as an inode path lock is released, which creates too many journal persistence/ raft RPCs and may impair the metadata sync performance. Hence, this class only flushes journals async on flush() and close() and the underlying journals in the async journal writer will be committed when the underlying JournalContext gets closed. Each metadata sync thread should have its own MetadataSyncMergeJournalContext instance.

Field Summary

Fields inherited from class alluxio.master.journal.FileSystemMergeJournalContext

mJournalEntryMerger

Constructor Summary

Constructors

Constructor and Description
MetadataSyncMergeJournalContext(JournalContext journalContext, JournalEntryMerger journalEntryMerger) Constructs a MetadataSyncMergeJournalContext.

Method Summary

Modifier and Type	Method and Description
void	close()
void	flush() Merges all journals and then flushes them.
JournalEntryMerger	getMerger()

Methods inherited from class alluxio.master.journal.FileSystemMergeJournalContext

append, appendMergedJournals, getUnderlyingJournalContext

Methods inherited from class java.lang.Object

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

Methods inherited from interface alluxio.master.journal.JournalContext

get

Constructor Detail

MetadataSyncMergeJournalContext

public MetadataSyncMergeJournalContext(JournalContext journalContext,
                                       JournalEntryMerger journalEntryMerger)

Constructs a MetadataSyncMergeJournalContext.

Parameters:

journalContext - the journal context to wrap

journalEntryMerger - the merger which merges multiple journal entries into one

Method Detail

flush

public void flush()

Description copied from class: FileSystemMergeJournalContext

Merges all journals and then flushes them. The journal writer will commit these journals synchronously.

Specified by:

flush in interface JournalContext

Overrides:

flush in class FileSystemMergeJournalContext

close

public void close()

Specified by:

close in interface JournalContext

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class FileSystemMergeJournalContext

getMerger

public JournalEntryMerger getMerger()

Returns:

the journal merger, used in unit test