alluxio.master.metastore.caching

Class CachingInodeStore

java.lang.Object

alluxio.master.metastore.caching.CachingInodeStore

All Implemented Interfaces:

Checkpointed, InodeStore, ReadOnlyInodeStore, Closeable, AutoCloseable

@ThreadSafe
public final class CachingInodeStore
extends Object
implements InodeStore, Closeable

An inode store which caches inode tree metadata and delegates to another inode store for cache misses. We call the other inode store the backing store. Backing store operations are much slower than on-heap operations, so we aim to serve as many requests as possible from the cache. When the inode tree fits completely within the cache, we never interact with the backing store, so performance should be similar to HeapInodeStore. Once the cache reaches the high watermark, we begin evicting metadata to the backing store, and performance becomes dependent on cache hit rate and backing store performance.

Implementation

The CachingInodeStore uses 3 caches: an inode cache, and edge cache, and a listing cache. The inode cache stores inode metadata such as inode names, permissions, and sizes. The edge cache stores edge metadata, i.e. which inodes are children of which other inodes. The listing cache caches the results of calling getChildren. See the javadoc for InodeCache, EdgeCache, and ListingCache for details about their inner workings.

Nested Class Summary

Nested classes/interfaces inherited from interface alluxio.master.metastore.InodeStore

InodeStore.Factory, InodeStore.WriteBatch

Constructor Summary

Constructors

Constructor and Description
CachingInodeStore(InodeStore backingStore, InodeLockManager lockManager)

Method Summary

Modifier and Type	Method and Description
void	addChild(long parentId, String childName, Long childId) Makes an inode the child of the specified parent.
Set<EdgeEntry>	allEdges()
Set<MutableInode<?>>	allInodes()
void	clear() Removes all inodes and edges.
void	close()
CheckpointName	getCheckpointName()
Optional<Inode>	getChild(Long inodeId, String name, ReadOption option)
Optional<Long>	getChildId(Long inodeId, String name, ReadOption option)
Iterable<Long>	getChildIds(Long inodeId, ReadOption option) Returns an iterable for the ids of the children of the given directory.
Optional<MutableInode<?>>	getMutable(long id, ReadOption option) Gets a mutable representation of the specified inode.
boolean	hasChildren(InodeDirectoryView inode, ReadOption option)
void	remove(Long inodeId) Removes an inode from the inode store.
void	removeChild(long parentId, String name) Removes a child from a parent inode.
void	restoreFromCheckpoint(CheckpointInputStream input) Restores state from a checkpoint.
void	writeInode(MutableInode<?> inode) Adds the given inode, or overwrites it if it already exists.
void	writeNewInode(MutableInode<?> inode) Adds a new inode.
void	writeToCheckpoint(OutputStream output) Writes a checkpoint of all state to the given output stream.

Methods inherited from class java.lang.Object

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

Methods inherited from interface alluxio.master.metastore.InodeStore

addChild, createWriteBatch, get, getMutable, remove, removeInodeAndParentEdge, supportsBatchWrite

Methods inherited from interface alluxio.master.metastore.ReadOnlyInodeStore

get, getChild, getChild, getChild, getChildId, getChildId, getChildId, getChildIds, getChildIds, getChildIds, getChildren, getChildren, getChildren, getChildren, hasChildren

Constructor Detail

CachingInodeStore

public CachingInodeStore(InodeStore backingStore,
                         InodeLockManager lockManager)

Parameters:

backingStore - the backing inode store

lockManager - inode lock manager

Method Detail

getMutable

public Optional<MutableInode<?>> getMutable(long id,
                                            ReadOption option)

Description copied from interface: InodeStore

Gets a mutable representation of the specified inode. Mutating the returned inode requires holding an inode lock manager read or write lock on the inode.

Specified by:

getMutable in interface InodeStore

Parameters:

id - an inode id

option - read options

Returns:

the inode with the given id, if it exists

remove

public void remove(Long inodeId)

Description copied from interface: InodeStore

Removes an inode from the inode store. This does *not* remove the edge leading to the inode. This method requires an inode lock manager read or write lock on the removed inode.

Specified by:

remove in interface InodeStore

Parameters:

inodeId - an inode to remove

writeInode

public void writeInode(MutableInode<?> inode)

Description copied from interface: InodeStore

Adds the given inode, or overwrites it if it already exists. If it is known that the inode is new, prefer InodeStore.writeNewInode(MutableInode). This method requires an inode lock manager read or write lock on the written inode.

Specified by:

writeInode in interface InodeStore

Parameters:

inode - the inode to write

writeNewInode

public void writeNewInode(MutableInode<?> inode)

Description copied from interface: InodeStore

Adds a new inode. This method is similar to InodeStore.writeInode(MutableInode), but with an added information that the inode is new. This allows some inode stores to perform extra optimizations. This method requires an inode lock manager read or write lock on the written inode.

Specified by:

writeNewInode in interface InodeStore

Parameters:

inode - the inode to write

clear

public void clear()

Description copied from interface: InodeStore

Removes all inodes and edges.

Specified by:

clear in interface InodeStore

addChild

public void addChild(long parentId,
                     String childName,
                     Long childId)

Description copied from interface: InodeStore

Makes an inode the child of the specified parent. This method requires an inode lock manager read or write locks on the added edge.

Specified by:

addChild in interface InodeStore

Parameters:

parentId - the parent id

childName - the child name

childId - the child inode id

removeChild

public void removeChild(long parentId,
                        String name)

Description copied from interface: InodeStore

Removes a child from a parent inode. This method requires an inode lock manager read or write locks on the removed edge.

Specified by:

removeChild in interface InodeStore

Parameters:

parentId - the parent inode id

name - the child name

getChildIds

public Iterable<Long> getChildIds(Long inodeId,
                                  ReadOption option)

Description copied from interface: ReadOnlyInodeStore

Returns an iterable for the ids of the children of the given directory.

Specified by:

getChildIds in interface ReadOnlyInodeStore

Parameters:

inodeId - an inode id to list child ids for

option - the options

Returns:

the child ids iterable

getChildId

public Optional<Long> getChildId(Long inodeId,
                                 String name,
                                 ReadOption option)

Specified by:

getChildId in interface ReadOnlyInodeStore

Parameters:

inodeId - an inode id

name - an inode name

option - the options

Returns:

the id of the child of the inode with the given name

getChild

public Optional<Inode> getChild(Long inodeId,
                                String name,
                                ReadOption option)

Specified by:

getChild in interface ReadOnlyInodeStore

Parameters:

inodeId - an inode id

name - an inode name

option - the options

Returns:

the child of the inode with the given name

hasChildren

public boolean hasChildren(InodeDirectoryView inode,
                           ReadOption option)

Specified by:

hasChildren in interface ReadOnlyInodeStore

Parameters:

inode - an inode directory

option - the options

Returns:

whether the inode has any children

allEdges

public Set<EdgeEntry> allEdges()

Specified by:

allEdges in interface ReadOnlyInodeStore

Returns:

all edges in the inode store

allInodes

public Set<MutableInode<?>> allInodes()

Specified by:

allInodes in interface ReadOnlyInodeStore

Returns:

all inodes in the inode store

close

public void close()

Specified by:

close in interface InodeStore

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

getCheckpointName

public CheckpointName getCheckpointName()

Specified by:

getCheckpointName in interface Checkpointed

Returns:

a name for this checkpointed class

writeToCheckpoint

public void writeToCheckpoint(OutputStream output)
                       throws IOException,
                              InterruptedException

Description copied from interface: Checkpointed

Writes a checkpoint of all state to the given output stream. Implementations should make an effort to throw InterruptedException if they get interrupted while running.

Specified by:

writeToCheckpoint in interface Checkpointed

Parameters:

output - the output stream to write to

Throws:

IOException

InterruptedException

restoreFromCheckpoint

public void restoreFromCheckpoint(CheckpointInputStream input)
                           throws IOException

Description copied from interface: Checkpointed

Restores state from a checkpoint.

Specified by:

restoreFromCheckpoint in interface Checkpointed

Parameters:

input - an input stream with checkpoint data

Throws:

IOException