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, boolean read)
GridCacheMvccCandidate	addLocal(GridCacheEntryEx parent, UUID nearNodeId, GridCacheVersion nearVer, long threadId, GridCacheVersion ver, long timeout, GridCacheVersion serOrder, boolean reenter, boolean tx, boolean implicitSingle, boolean dhtLoc, boolean read)
GridCacheMvccCandidate	addNearLocal(GridCacheEntryEx parent, UUID nodeId, UUID otherNodeId, long threadId, GridCacheVersion ver, boolean tx, boolean implicitSingle, boolean read) Adds new near local lock candidate.
GridCacheMvccCandidate	addRemote(GridCacheEntryEx parent, UUID nodeId, UUID otherNodeId, long threadId, GridCacheVersion ver, boolean tx, boolean implicitSingle, boolean nearLoc) Adds new remote lock candidate (either near remote or dht remote).
CacheLockCandidates	allOwners()
GridCacheMvccCandidate	candidate(GridCacheVersion ver) Gets candidate for lock ID.
CacheLockCandidates	doneRemote(GridCacheVersion ver, Collection<GridCacheVersion> pending, Collection<GridCacheVersion> committed, Collection<GridCacheVersion> rolledback) Sets remote candidate to done.
boolean	isEmpty(GridCacheVersion... exclude)
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)
CacheLockCandidates	localOwners()
void	markOwned(GridCacheVersion baseVer, GridCacheVersion owned) Puts owned versions in front of base.
void	orderCompleted(GridCacheVersion baseVer, Collection<GridCacheVersion> committedVers, Collection<GridCacheVersion> rolledbackVers) Moves completed candidates right before the base one.
CacheLockCandidates	readyLocal(GridCacheMvccCandidate cand)
CacheLockCandidates	readyLocal(GridCacheVersion ver)
CacheLockCandidates	readyNearLocal(GridCacheVersion ver, GridCacheVersion mappedVer, Collection<GridCacheVersion> committedVers, Collection<GridCacheVersion> rolledBackVers, Collection<GridCacheVersion> pending) Marks near-local candidate as ready and makes locks reassignment.
CacheLockCandidates	recheck() Checks if lock should be assigned.
GridCacheMvccCandidate	releaseLocal() Local local release.
GridCacheMvccCandidate	releaseLocal(long threadId) Local release.
List<GridCacheMvccCandidate>	remoteCandidates(GridCacheVersion... excludeVers)
void	remove(GridCacheVersion ver) Removes lock even if it is not owner.
CacheLockCandidates	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

allOwners

@Nullable
public CacheLockCandidates allOwners()

Returns:

All owners.

localOwners

@Nullable
public CacheLockCandidates localOwners()

Returns:

All local owners.

isEmpty

public boolean isEmpty(GridCacheVersion... exclude)

Parameters:

exclude - Versions to exclude form check.

Returns:

True if lock is empty.

orderCompleted

public void 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.

markOwned

public void markOwned(GridCacheVersion baseVer,
             GridCacheVersion owned)

Puts owned versions in front of base.

Parameters:

baseVer - Base version.

owned - Owned list.

addLocal

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

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.

read - Read lock 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,
                                       boolean read)

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.

read - Read lock 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,
                               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.

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,
                                  boolean tx,
                                  boolean implicitSingle,
                                  boolean read)

Adds new near local lock candidate.

Parameters:

parent - Parent entry.

nodeId - Node ID.

otherNodeId - Other node ID.

threadId - Thread ID.

ver - Lock version.

tx - Transaction flag.

implicitSingle - Implicit flag.

read - Read lock flag.

Returns:

Add remote candidate.

readyLocal

@Nullable
public CacheLockCandidates readyLocal(GridCacheVersion ver)

Parameters:

ver - Lock version to acquire or set to ready.

Returns:

Current owner.

readyLocal

@Nullable
public CacheLockCandidates readyLocal(GridCacheMvccCandidate cand)

Parameters:

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

Returns:

Current lock owner.

readyNearLocal

@Nullable
public CacheLockCandidates 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 CacheLockCandidates 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 CacheLockCandidates recheck()

Checks if lock should be assigned.

Returns:

Owner.

releaseLocal

@Nullable
public GridCacheMvccCandidate releaseLocal()

Local local release.

Returns:

Removed candidate.

releaseLocal

@Nullable
public GridCacheMvccCandidate releaseLocal(long threadId)

Local release.

Parameters:

threadId - ID of the thread.

Returns:

Removed candidate.

remove

public void remove(GridCacheVersion ver)

Removes lock even if it is not owner.

Parameters:

ver - Lock version.

removeExplicitNodeCandidates

@Nullable
public CacheLockCandidates 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(UUID nodeId,
                                             long threadId)

Near local candidate.

Parameters:

nodeId - Node ID.

threadId - Thread ID.

Returns:

Remote candidate.

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.

toString

public String toString()

Overrides:

toString in class Object