org.apache.jackrabbit.oak.plugins.segment

Class PersistedCompactionMap

java.lang.Object

org.apache.jackrabbit.oak.plugins.segment.PersistedCompactionMap

All Implemented Interfaces:

PartialCompactionMap

public class PersistedCompactionMap
extends java.lang.Object
implements PartialCompactionMap

A PartialCompactionMap implementation persisting its entries to segments. TODO In theory we could also compact the compaction map. Is there any need to do so?

Field Summary

Fields

Modifier and Type	Field and Description
static int	BYTES_PER_ENTRY Rough estimate of the number of bytes of disk space of a map entry.
static java.lang.String	PERSISTED_COMPACTION_MAP Key used to store meta data associated with the individual map generations.

Method Summary

Modifier and Type	Method and Description
void	compress() Compressing this map ensures it takes up as little heap as possible.
RecordId	get(RecordId before) Retrieve the record id before maps to or null if no such id exists.
long	getEstimatedWeight() The weight of the compaction map is its heap memory consumption in bytes.
long	getRecordCount() Number of records referenced by the keys in this map.
long	getSegmentCount() Number of segments referenced by the keys in this map.
boolean	isEmpty() Determine whether this map contains keys at all.
void	put(RecordId before, RecordId after) Adds a new entry to the compaction map.
void	remove(java.util.Set<java.util.UUID> uuids) Remove all keys from this map where keys.contains(key.asUUID()).
boolean	wasCompacted(java.util.UUID uuid) Checks whether content in the segment with the given identifier was compacted to new segments.
boolean	wasCompactedTo(RecordId before, RecordId after) Checks whether the record with the given before identifier was compacted to a new record with the given after identifier.

Methods inherited from class java.lang.Object

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

Field Detail

BYTES_PER_ENTRY

public static final int BYTES_PER_ENTRY

Rough estimate of the number of bytes of disk space of a map entry. Used by the compaction gain estimator to offset its estimate.

PERSISTED_COMPACTION_MAP

public static final java.lang.String PERSISTED_COMPACTION_MAP

Key used to store meta data associated with the individual map generations. Tools can use this to grep across segments for finding the meta data and ultimately to find and parse the compaction map generations.

See Also:

Constant Field Values

Method Detail

wasCompactedTo

public boolean wasCompactedTo(RecordId before,
                              RecordId after)

Description copied from interface: PartialCompactionMap

Checks whether the record with the given before identifier was compacted to a new record with the given after identifier.

Specified by:

wasCompactedTo in interface PartialCompactionMap

Parameters:

before - before record identifier

after - after record identifier

Returns:

whether before was compacted to after

wasCompacted

public boolean wasCompacted(java.util.UUID uuid)

Description copied from interface: PartialCompactionMap

Checks whether content in the segment with the given identifier was compacted to new segments.

Specified by:

wasCompacted in interface PartialCompactionMap

Parameters:

uuid - segment identifier

Returns:

whether the identified segment was compacted

get

public RecordId get(RecordId before)

Description copied from interface: PartialCompactionMap

Retrieve the record id before maps to or null if no such id exists.

Specified by:

get in interface PartialCompactionMap

Parameters:

before - before record id

Returns:

after record id or null

put

public void put(RecordId before,
                RecordId after)

Description copied from interface: PartialCompactionMap

Adds a new entry to the compaction map. Overwriting a previously added entry is not supported.

Specified by:

put in interface PartialCompactionMap

Parameters:

before - before record id

after - after record id

remove

public void remove(java.util.Set<java.util.UUID> uuids)

Description copied from interface: PartialCompactionMap

Remove all keys from this map where keys.contains(key.asUUID()).

Specified by:

remove in interface PartialCompactionMap

Parameters:

uuids - uuids of the keys to remove

compress

public void compress()

Description copied from interface: PartialCompactionMap

Compressing this map ensures it takes up as little heap as possible. This operation might be expensive and should only be called in suitable intervals.

Specified by:

compress in interface PartialCompactionMap

getSegmentCount

public long getSegmentCount()

Description copied from interface: PartialCompactionMap

Number of segments referenced by the keys in this map. The returned value might only be based on the compressed part of the map.

Specified by:

getSegmentCount in interface PartialCompactionMap

Returns:

number of segments

getRecordCount

public long getRecordCount()

Description copied from interface: PartialCompactionMap

Number of records referenced by the keys in this map. The returned value might only be based on the compressed part of the map.

Specified by:

getRecordCount in interface PartialCompactionMap

Returns:

number of records

isEmpty

public boolean isEmpty()

Description copied from interface: PartialCompactionMap

Determine whether this map contains keys at all.

Specified by:

isEmpty in interface PartialCompactionMap

Returns:

true iff this map is empty

getEstimatedWeight

public long getEstimatedWeight()

Description copied from interface: PartialCompactionMap

The weight of the compaction map is its heap memory consumption in bytes.

Specified by:

getEstimatedWeight in interface PartialCompactionMap

Returns:

0