org.apache.ignite.internal.processors.cache

Class GridCacheMvcc

java.lang.Object

org.apache.ignite.internal.processors.cache.GridCacheMvcc

public final class GridCacheMvcc
extends Object

Replicated lock based on MVCC paradigm. This class ensures that locks are acquired in proper order and that there is no more than only one active lock present at all times. It also ensures that new generated lock candidates will appear after old ones in the pending set, hence preventing lock starvation. See GridCacheVersionManager.next() for information on how lock IDs are generated to prevent starvation.

Constructor Summary

Constructors

Constructor and Description
GridCacheMvcc(GridCacheContext<?,?> cctx)

Method Summary

Methods

Modifier and Type	Method and Description
GridCacheMvccCandidate	addLocal(GridCacheEntryEx parent, long threadId, GridCacheVersion ver, long timeout, boolean reenter, boolean tx, boolean implicitSingle)
GridCacheMvccCandidate	addLocal(GridCacheEntryEx parent, UUID nearNodeId, GridCacheVersion nearVer, long threadId, GridCacheVersion ver, long timeout, GridCacheVersion serOrder, boolean reenter, boolean tx, boolean implicitSingle, boolean dhtLoc)
GridCacheMvccCandidate	addNearLocal(GridCacheEntryEx parent, UUID nodeId, UUID otherNodeId, long threadId, GridCacheVersion ver, long timeout, boolean tx, boolean implicitSingle) Adds new near local lock candidate.
GridCacheMvccCandidate	addRemote(GridCacheEntryEx parent, UUID nodeId, UUID otherNodeId, long threadId, GridCacheVersion ver, long timeout, boolean tx, boolean implicitSingle, boolean nearLoc) Adds new remote lock candidate (either near remote or dht remote).
void	addRemote(GridCacheMvccCandidate cand)
List<GridCacheMvccCandidate>	allLocal()
GridCacheMvccCandidate	anyOwner()
GridCacheMvccCandidate	candidate(GridCacheVersion ver) Gets candidate for lock ID.
GridCacheMvccCandidate	doneRemote(GridCacheVersion ver, Collection<GridCacheVersion> pending, Collection<GridCacheVersion> committed, Collection<GridCacheVersion> rolledback) Sets remote candidate to done.
GridCacheMvccCandidate	firstLocal()
GridCacheMvccCandidate	firstRemote()
boolean	hasCandidate(GridCacheVersion ver)
boolean	isEmpty(GridCacheVersion... exclude)
boolean	isLocallyOwned(GridCacheVersion lockVer)
boolean	isLocallyOwnedByCurrentThread()
boolean	isLocallyOwnedByIdOrThread(GridCacheVersion lockVer, long threadId)
boolean	isLocallyOwnedByThread(long threadId, boolean allowDhtLoc, GridCacheVersion... exclude)
boolean	isLockedByThread(long threadId, UUID nodeId)
boolean	isOwnedBy(GridCacheVersion ver)
boolean	isOwnedByAny()
GridCacheMvccCandidate	localCandidate(long threadId) Gets candidate for lock ID.
GridCacheMvccCandidate	localCandidate(UUID nodeId, long threadId) Near local candidate.
List<GridCacheMvccCandidate>	localCandidates(boolean reentries, GridCacheVersion... excludeVers)
Collection<GridCacheMvccCandidate>	localCandidates(GridCacheVersion... excludeVers)
List<GridCacheMvccCandidate>	localCandidatesNoCopy(boolean reentry)
GridCacheMvccCandidate	localOwner()
GridCacheMvccCandidate	markOwned(GridCacheVersion baseVer, GridCacheVersion owned) Puts owned versions in front of base.
GridCacheMvccCandidate	orderCompleted(GridCacheVersion baseVer, Collection<GridCacheVersion> committedVers, Collection<GridCacheVersion> rolledbackVers) Moves completed candidates right before the base one.
GridCacheMvccCandidate	readyLocal(GridCacheMvccCandidate cand)
GridCacheMvccCandidate	readyLocal(GridCacheVersion ver)
GridCacheMvccCandidate	readyNearLocal(GridCacheVersion ver, GridCacheVersion mappedVer, Collection<GridCacheVersion> committedVers, Collection<GridCacheVersion> rolledBackVers, Collection<GridCacheVersion> pending) Marks near-local candidate as ready and makes locks reassignment.
GridCacheMvccCandidate	recheck() Checks if lock should be assigned.
GridCacheMvccCandidate	releaseLocal() Local local release.
GridCacheMvccCandidate	releaseLocal(long threadId) Local release.
GridCacheMvccCandidate	remoteCandidate(UUID nodeId, long threadId)
List<GridCacheMvccCandidate>	remoteCandidates(GridCacheVersion... excludeVers)
GridCacheMvccCandidate	remoteOwner()
GridCacheMvccCandidate	remove(GridCacheVersion ver) Removes lock even if it is not owner.
GridCacheMvccCandidate	removeExplicitNodeCandidates(UUID nodeId) Removes all candidates for node.
void	salvageRemote(GridCacheVersion ver) For all remote candidates standing behind the candidate being salvaged marks their transactions as system invalidate and marks these candidates as owned and used.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

GridCacheMvcc

public GridCacheMvcc(GridCacheContext<?,?> cctx)

Parameters:

cctx - Cache context.

Method Detail

anyOwner

@Nullable
public GridCacheMvccCandidate anyOwner()

Returns:

Any owner.

remoteOwner

@Nullable
public GridCacheMvccCandidate remoteOwner()

Returns:

Remote candidate only if it's first in the list and is marked as 'used'.

localOwner

@Nullable
public GridCacheMvccCandidate localOwner()

Returns:

Local candidate only if it's first in the list and is marked as 'owner'.

isEmpty

public boolean isEmpty(GridCacheVersion... exclude)

Parameters:

exclude - Versions to exclude form check.

Returns:

True if lock is empty.

orderCompleted

@Nullable
public GridCacheMvccCandidate orderCompleted(GridCacheVersion baseVer,
                                             Collection<GridCacheVersion> committedVers,
                                             Collection<GridCacheVersion> rolledbackVers)

Moves completed candidates right before the base one. Note that if base is not found, then nothing happens and false is returned.

Parameters:

baseVer - Base version.

committedVers - Committed versions relative to base.

rolledbackVers - Rolled back versions relative to base.

Returns:

Lock owner.

markOwned

@Nullable
public GridCacheMvccCandidate markOwned(GridCacheVersion baseVer,
                                        GridCacheVersion owned)

Puts owned versions in front of base.

Parameters:

baseVer - Base version.

owned - Owned list.

Returns:

Current owner.

addLocal

@Nullable
public GridCacheMvccCandidate addLocal(GridCacheEntryEx parent,
                                       long threadId,
                                       GridCacheVersion ver,
                                       long timeout,
                                       boolean reenter,
                                       boolean tx,
                                       boolean implicitSingle)

Parameters:

parent - Parent entry.

threadId - Thread ID.

ver - Lock version.

timeout - Lock acquisition timeout.

reenter - Reentry flag (true if reentry is allowed).

tx - Transaction flag.

implicitSingle - Implicit transaction flag.

Returns:

New lock candidate if lock was added, or current owner if lock was reentered, or null if lock was owned by another thread and timeout is negative.

addLocal

@Nullable
public GridCacheMvccCandidate addLocal(GridCacheEntryEx parent,
                                       @Nullable
                                       UUID nearNodeId,
                                       @Nullable
                                       GridCacheVersion nearVer,
                                       long threadId,
                                       GridCacheVersion ver,
                                       long timeout,
                                       @Nullable
                                       GridCacheVersion serOrder,
                                       boolean reenter,
                                       boolean tx,
                                       boolean implicitSingle,
                                       boolean dhtLoc)

Parameters:

parent - Parent entry.

nearNodeId - Near node ID.

nearVer - Near version.

threadId - Thread ID.

ver - Lock version.

timeout - Lock acquisition timeout.

serOrder - Version for serializable transactions ordering.

reenter - Reentry flag (true if reentry is allowed).

tx - Transaction flag.

implicitSingle - Implicit flag.

dhtLoc - DHT local flag.

Returns:

New lock candidate if lock was added, or current owner if lock was reentered, or null if lock was owned by another thread and timeout is negative.

addRemote

public GridCacheMvccCandidate addRemote(GridCacheEntryEx parent,
                               UUID nodeId,
                               @Nullable
                               UUID otherNodeId,
                               long threadId,
                               GridCacheVersion ver,
                               long timeout,
                               boolean tx,
                               boolean implicitSingle,
                               boolean nearLoc)

Adds new remote lock candidate (either near remote or dht remote).

Parameters:

parent - Parent entry.

nodeId - Node ID.

otherNodeId - Other node ID.

threadId - Thread ID.

ver - Lock version.

timeout - Lock acquire timeout.

tx - Transaction flag.

implicitSingle - Implicit flag.

nearLoc - Near local flag.

Returns:

Add remote candidate.

addNearLocal

public GridCacheMvccCandidate addNearLocal(GridCacheEntryEx parent,
                                  UUID nodeId,
                                  @Nullable
                                  UUID otherNodeId,
                                  long threadId,
                                  GridCacheVersion ver,
                                  long timeout,
                                  boolean tx,
                                  boolean implicitSingle)

Adds new near local lock candidate.

Parameters:

parent - Parent entry.

nodeId - Node ID.

otherNodeId - Other node ID.

threadId - Thread ID.

ver - Lock version.

timeout - Lock acquire timeout.

tx - Transaction flag.

implicitSingle - Implicit flag.

Returns:

Add remote candidate.

addRemote

public void addRemote(GridCacheMvccCandidate cand)

Parameters:

cand - Remote candidate.

readyLocal

@Nullable
public GridCacheMvccCandidate readyLocal(GridCacheVersion ver)

Parameters:

ver - Lock version to acquire or set to ready.

Returns:

Current owner.

readyLocal

@Nullable
public GridCacheMvccCandidate readyLocal(GridCacheMvccCandidate cand)

Parameters:

cand - Local candidate added in any of the addLocal(..) methods.

Returns:

Current lock owner.

readyNearLocal

@Nullable
public GridCacheMvccCandidate readyNearLocal(GridCacheVersion ver,
                                             GridCacheVersion mappedVer,
                                             Collection<GridCacheVersion> committedVers,
                                             Collection<GridCacheVersion> rolledBackVers,
                                             Collection<GridCacheVersion> pending)

Marks near-local candidate as ready and makes locks reassignment. Following reorderings are performed when candidate is marked ready:

• All candidates preceding ready one are moved right after it.
• Near local candidate is assigned a mapped dht version. All remote non-pending candidates with version less then mapped dht version are marked as owned.

Parameters:

ver - Version to mark as ready.

mappedVer - Mapped dht version.

committedVers - Committed versions.

rolledBackVers - Rolled back versions.

pending - Pending dht versions that are not owned and which version is less then mapped.

Returns:

Lock owner after reassignment.

doneRemote

@Nullable
public GridCacheMvccCandidate doneRemote(GridCacheVersion ver,
                                         Collection<GridCacheVersion> pending,
                                         Collection<GridCacheVersion> committed,
                                         Collection<GridCacheVersion> rolledback)

Sets remote candidate to done.

Parameters:

ver - Version.

pending - Pending versions.

committed - Committed versions.

rolledback - Rolledback versions.

Returns:

Lock owner.

salvageRemote

public void salvageRemote(GridCacheVersion ver)

For all remote candidates standing behind the candidate being salvaged marks their transactions as system invalidate and marks these candidates as owned and used.

Parameters:

ver - Version to salvage.

recheck

@Nullable
public GridCacheMvccCandidate recheck()

Checks if lock should be assigned.

Returns:

Owner.

releaseLocal

@Nullable
public GridCacheMvccCandidate releaseLocal()

Local local release.

Returns:

Removed lock candidate or null if candidate was not removed.

releaseLocal

@Nullable
public GridCacheMvccCandidate releaseLocal(long threadId)

Local release.

Parameters:

threadId - ID of the thread.

Returns:

Current owner.

remove

@Nullable
public GridCacheMvccCandidate remove(GridCacheVersion ver)

Removes lock even if it is not owner.

Parameters:

ver - Lock version.

Returns:

Current owner.

removeExplicitNodeCandidates

@Nullable
public GridCacheMvccCandidate removeExplicitNodeCandidates(UUID nodeId)

Removes all candidates for node.

Parameters:

nodeId - Node ID.

Returns:

Current owner.

candidate

@Nullable
public GridCacheMvccCandidate candidate(GridCacheVersion ver)

Gets candidate for lock ID.

Parameters:

ver - Lock version.

Returns:

Candidate or null if there is no candidate for given ID.

localCandidate

@Nullable
public GridCacheMvccCandidate localCandidate(long threadId)

Gets candidate for lock ID.

Parameters:

threadId - Thread ID.

Returns:

Candidate or null if there is no candidate for given ID.

remoteCandidate

@Nullable
public GridCacheMvccCandidate remoteCandidate(UUID nodeId,
                                              long threadId)

Parameters:

nodeId - Node ID.

threadId - Thread ID.

Returns:

Remote candidate.

localCandidate

@Nullable
public GridCacheMvccCandidate localCandidate(UUID nodeId,
                                             long threadId)

Near local candidate.

Parameters:

nodeId - Node ID.

threadId - Thread ID.

Returns:

Remote candidate.

hasCandidate

public boolean hasCandidate(GridCacheVersion ver)

Parameters:

ver - Version.

Returns:

True if candidate with given version exists.

localCandidatesNoCopy

public List<GridCacheMvccCandidate> localCandidatesNoCopy(boolean reentry)

Parameters:

reentry - Reentry flag.

Returns:

Collection of local candidates.

localCandidates

public Collection<GridCacheMvccCandidate> localCandidates(GridCacheVersion... excludeVers)

Parameters:

excludeVers - Exclude versions.

Returns:

Collection of local candidates.

localCandidates

public List<GridCacheMvccCandidate> localCandidates(boolean reentries,
                                           GridCacheVersion... excludeVers)

Parameters:

reentries - Flag to include reentries.

excludeVers - Exclude versions.

Returns:

Collection of local candidates.

remoteCandidates

public List<GridCacheMvccCandidate> remoteCandidates(GridCacheVersion... excludeVers)

Parameters:

excludeVers - Exclude versions.

Returns:

Collection of remote candidates.

isLocallyOwnedByCurrentThread

public boolean isLocallyOwnedByCurrentThread()

Returns:

True if lock is owner by current thread.

isLocallyOwnedByThread

public boolean isLocallyOwnedByThread(long threadId,
                             boolean allowDhtLoc,
                             GridCacheVersion... exclude)

Parameters:

threadId - Thread ID to check.

exclude - Versions to ignore.

Returns:

True if lock is owned by the thread with given ID.

isLockedByThread

public boolean isLockedByThread(long threadId,
                       UUID nodeId)

Parameters:

threadId - Thread ID.

nodeId - Node ID.

Returns:

True if lock is held by given thread and node IDs.

isOwnedByAny

public boolean isOwnedByAny()

Returns:

True if lock is owned by any thread or node.

isLocallyOwned

public boolean isLocallyOwned(GridCacheVersion lockVer)

Parameters:

lockVer - ID of lock candidate.

Returns:

True if candidate is owner.

isLocallyOwnedByIdOrThread

public boolean isLocallyOwnedByIdOrThread(GridCacheVersion lockVer,
                                 long threadId)

Parameters:

lockVer - Lock ID.

threadId - Thread ID.

Returns:

True if locked by lock ID or thread ID.

firstRemote

@Nullable
public GridCacheMvccCandidate firstRemote()

Returns:

First remote entry or null.

firstLocal

@Nullable
public GridCacheMvccCandidate firstLocal()

Returns:

First local entry or null.

allLocal

@Nullable
public List<GridCacheMvccCandidate> allLocal()

Returns:

Local MVCC candidates.

isOwnedBy

public boolean isOwnedBy(GridCacheVersion ver)

Parameters:

ver - Version to check for ownership.

Returns:

True if lock is owned by the specified version.

toString

public String toString()

Overrides:

toString in class Object