Package org.apache.jackrabbit.oak.segment

Class CheckpointCompactor

java.lang.Object

org.apache.jackrabbit.oak.segment.Compactor

org.apache.jackrabbit.oak.segment.CheckpointCompactor

Direct Known Subclasses:

ParallelCompactor

public class CheckpointCompactor
extends Compactor

This compactor implementation is aware of the checkpoints in the repository. It uses this information to further optimise the compaction result by

• Rebasing the checkpoints and subsequently the root on top of each other in chronological order. This results minimises the deltas that need to be processed and stored.
• Caching the compacted checkpoints and root states for deduplication should the same checkpoint or root state occur again in a later compaction retry cycle.

Field Summary

Fields

Modifier and Type	Field	Description
protected @NotNull ClassicCompactor	compactor
protected @NotNull GCMonitor	gcListener

Constructor Summary

Constructors

Constructor	Description
CheckpointCompactor(@NotNull GCMonitor gcListener, @NotNull CompactionWriter writer, @NotNull GCNodeWriteMonitor compactionMonitor)	Create a new instance based on the passed arguments.

Method Summary

Modifier and Type	Method	Description
@Nullable CompactedNodeState	compact(@NotNull NodeState before, @NotNull NodeState after, @NotNull NodeState onto, @NotNull Canceller canceller)	compact the differences between after and before on top of onto.
@Nullable CompactedNodeState	compactDown(@NotNull NodeState before, @NotNull NodeState after, @NotNull Canceller hardCanceller, @NotNull Canceller softCanceller)	compact the differences between after and before on top of after.
protected @Nullable CompactedNodeState	compactDownWithDelegate(@NotNull NodeState before, @NotNull NodeState after, @NotNull Canceller hardCanceller, @NotNull Canceller softCanceller)	Delegate compaction to another, usually simpler, implementation.
protected @Nullable CompactedNodeState	compactWithDelegate(@NotNull NodeState before, @NotNull NodeState after, @NotNull NodeState onto, @NotNull Canceller canceller)

Methods inherited from class org.apache.jackrabbit.oak.segment.Compactor

compactDown, compactUp, compactUp

Methods inherited from class java.lang.Object

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

Field Detail

gcListener

@NotNull
protected final @NotNull GCMonitor gcListener

compactor

@NotNull
protected final @NotNull ClassicCompactor compactor

Constructor Detail

CheckpointCompactor

public CheckpointCompactor(@NotNull
                           @NotNull GCMonitor gcListener,
                           @NotNull
                           @NotNull CompactionWriter writer,
                           @NotNull
                           @NotNull GCNodeWriteMonitor compactionMonitor)

Create a new instance based on the passed arguments.

Parameters:

gcListener - listener receiving notifications about the garbage collection process

writer - segment writer used to serialise to segments

compactionMonitor - notification call back for each compacted nodes, properties, and binaries

Method Detail

compactDown

@Nullable
public @Nullable CompactedNodeState compactDown(@NotNull
                                                @NotNull NodeState before,
                                                @NotNull
                                                @NotNull NodeState after,
                                                @NotNull
                                                @NotNull Canceller hardCanceller,
                                                @NotNull
                                                @NotNull Canceller softCanceller)
                                         throws java.io.IOException

Description copied from class: Compactor

compact the differences between after and before on top of after.

Specified by:

compactDown in class Compactor

Parameters:

before - the node state to diff against from after

after - the node state diffed against before

hardCanceller - the trigger for hard cancellation, will abandon compaction if cancelled

softCanceller - the trigger for soft cancellation, will return partially compacted state if cancelled

Returns:

the compacted node state or null if hard-cancelled

Throws:

java.io.IOException - will throw exception if any errors occur during compaction

compact

@Nullable
public @Nullable CompactedNodeState compact(@NotNull
                                            @NotNull NodeState before,
                                            @NotNull
                                            @NotNull NodeState after,
                                            @NotNull
                                            @NotNull NodeState onto,
                                            @NotNull
                                            @NotNull Canceller canceller)
                                     throws java.io.IOException

Description copied from class: Compactor

compact the differences between after and before on top of onto.

Specified by:

compact in class Compactor

Parameters:

before - the node state to diff against from after

after - the node state diffed against before

onto - the node state to compact to apply the diff to

canceller - the trigger for hard cancellation, will abandon compaction if cancelled

Returns:

the compacted node state or null if hard-cancelled

Throws:

java.io.IOException - will throw exception if any errors occur during compaction

compactDownWithDelegate

@Nullable
protected @Nullable CompactedNodeState compactDownWithDelegate(@NotNull
                                                               @NotNull NodeState before,
                                                               @NotNull
                                                               @NotNull NodeState after,
                                                               @NotNull
                                                               @NotNull Canceller hardCanceller,
                                                               @NotNull
                                                               @NotNull Canceller softCanceller)
                                                        throws java.io.IOException

Delegate compaction to another, usually simpler, implementation.

Throws:

java.io.IOException

compactWithDelegate

@Nullable
protected @Nullable CompactedNodeState compactWithDelegate(@NotNull
                                                           @NotNull NodeState before,
                                                           @NotNull
                                                           @NotNull NodeState after,
                                                           @NotNull
                                                           @NotNull NodeState onto,
                                                           @NotNull
                                                           @NotNull Canceller canceller)
                                                    throws java.io.IOException

Throws:

java.io.IOException