org.janusgraph.diskstorage.inmemory

Class MultiPageEntryBuffer

java.lang.Object

org.janusgraph.diskstorage.inmemory.MultiPageEntryBuffer

All Implemented Interfaces:

SharedEntryBuffer

public class MultiPageEntryBuffer
extends Object
implements SharedEntryBuffer

"Multi-page" implementation of SharedEntryBuffer. Maintains a list of pages, each containing a shared byte buffer for maxPageSize Entries. Dividing the buffer into pages helps maintain performance in the case of very big stores. This is because when mutating, instead of re-copying all the entries in a single byte buffer, we only locate and modify a few pages, skipping those not affected by the mutation.

Since only a limited number of stores actually get very big, the parent store switches from SinglePageEntryBuffer to this implementation when a mutation brings the max number of entries beyond maxPageSize threshold.

Constructor Summary

Constructors

Constructor and Description
MultiPageEntryBuffer(org.janusgraph.diskstorage.inmemory.BufferPage initialPage)

Method Summary

Modifier and Type	Method and Description
int	byteSize()
SharedEntryBufferFragmentationReport	createFragmentationReport(int maxPageSize)
void	dumpTo(DataOutputStream out)
EntryList	getSlice(KeySliceQuery query)
boolean	isEmpty()
boolean	isPaged()
void	mutate(Entry[] add, Entry[] del, int maxPageSize)
int	numEntries()
int	numPages()
void	quickDefragment(int maxPageSize)

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiPageEntryBuffer

public MultiPageEntryBuffer(org.janusgraph.diskstorage.inmemory.BufferPage initialPage)

Method Detail

numPages

public int numPages()

Specified by:

numPages in interface SharedEntryBuffer

numEntries

public int numEntries()

Specified by:

numEntries in interface SharedEntryBuffer

byteSize

public int byteSize()

Specified by:

byteSize in interface SharedEntryBuffer

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface SharedEntryBuffer

getSlice

public EntryList getSlice(KeySliceQuery query)

Specified by:

getSlice in interface SharedEntryBuffer

mutate

public void mutate(Entry[] add,
                   Entry[] del,
                   int maxPageSize)

Specified by:

mutate in interface SharedEntryBuffer

isPaged

public boolean isPaged()

Specified by:

isPaged in interface SharedEntryBuffer

createFragmentationReport

public SharedEntryBufferFragmentationReport createFragmentationReport(int maxPageSize)

Specified by:

createFragmentationReport in interface SharedEntryBuffer

quickDefragment

public void quickDefragment(int maxPageSize)

Specified by:

quickDefragment in interface SharedEntryBuffer

dumpTo

public void dumpTo(DataOutputStream out)
            throws IOException

Specified by:

dumpTo in interface SharedEntryBuffer

Throws:

IOException