com.persistit

Class Management.BufferInfo

java.lang.Object

com.persistit.Management.AcquisitionTimeBase

com.persistit.Management.BufferInfo

All Implemented Interfaces:

Serializable

Enclosing interface:

Management

public static class Management.BufferInfo
extends Management.AcquisitionTimeBase
implements Serializable

Exposes information about one Buffer. Use the Management.getBufferInfoArray(int, int, java.lang.String, java.lang.String) method to get an array of BufferInfo s for Buffers in various states.

Note that the content of a BufferPool and the status of individual Buffers changes extremely rapidly when Persistit is active. A BufferInfo represents a snapshot of this state at the acquisition time.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static long	serialVersionUID

Constructor Summary

Constructors

Constructor and Description
BufferInfo()
BufferInfo(int poolIndex, int type, String typeName, int status, String statusName, String writerThreadName, long pageAddress, long rightSiblingAddress, String volumeName, long volumeId, long timestamp, int bufferSize, int availableBytes, int alloc, int slack, int mvvCount, int mvvSize, int keyBlockStart, int keyBlockEnd)

Method Summary

Modifier and Type	Method and Description
String	displayableSummary() Return a human-readable summary of information about the page contained in this Buffer.
int	getAlloc()
int	getAvailableBytes()
int	getBufferSize()
int	getKeyBlockEnd() Return an offset within the Buffer used internally in allocating space for key/value pairs.
int	getKeyBlockStart() Return an offset within the Buffer used internally in allocating space for key/value pairs.
int	getMvvCount()
int	getMvvSize()
long	getPageAddress()
int	getPoolIndex() Return the index of this Buffer within the BufferPool array.
long	getRightSiblingAddress()
int	getSlack()
int	getStatus() Return the status integer for this Buffer.
String	getStatusName() Return the status of this Buffer in displayable form.
long	getTimestamp()
int	getType() Return the type of page occupying this Buffer as an integer.
String	getTypeName() Return the type of page occupying this Buffer in displayable name form.
long	getVolumeId()
String	getVolumeName()
String	getWriterThreadName() Return the name of the Thread that currently holds a writer (exclusive) claim on the Buffer if there is one, otherwise returns null.
boolean	isDataPage() Indicates whether the page occupying this buffer is a Data page.
boolean	isGarbagePage() Indicates whether the page occupying this buffer is a Garbage page.
boolean	isIndexPage() Indicates whether the page occupying this buffer is an Index page.
boolean	isLongRecordPage() Indicates whether the page occupying this buffer is a LongRecord page.
boolean	isUnallocatedPage() Indicates whether the page occupying this buffer is an Unallocated page.

Methods inherited from class com.persistit.Management.AcquisitionTimeBase

getAcquisitionTime, setAcquisitionTime

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

public static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

BufferInfo

public BufferInfo()

BufferInfo

@ConstructorProperties(value={"poolIndex","type","typeName","status","statusName","writerThreadName","pageAddress","rightSiblingAddress","volumeName","volumeId","timestamp","bufferSize","availableBytes","alloc","slack","mvvCount","mvvSize","keyBlockStart","keyBlockEnd"})
public BufferInfo(int poolIndex,
                                                                                                                                                                                                                                                                                                  int type,
                                                                                                                                                                                                                                                                                                  String typeName,
                                                                                                                                                                                                                                                                                                  int status,
                                                                                                                                                                                                                                                                                                  String statusName,
                                                                                                                                                                                                                                                                                                  String writerThreadName,
                                                                                                                                                                                                                                                                                                  long pageAddress,
                                                                                                                                                                                                                                                                                                  long rightSiblingAddress,
                                                                                                                                                                                                                                                                                                  String volumeName,
                                                                                                                                                                                                                                                                                                  long volumeId,
                                                                                                                                                                                                                                                                                                  long timestamp,
                                                                                                                                                                                                                                                                                                  int bufferSize,
                                                                                                                                                                                                                                                                                                  int availableBytes,
                                                                                                                                                                                                                                                                                                  int alloc,
                                                                                                                                                                                                                                                                                                  int slack,
                                                                                                                                                                                                                                                                                                  int mvvCount,
                                                                                                                                                                                                                                                                                                  int mvvSize,
                                                                                                                                                                                                                                                                                                  int keyBlockStart,
                                                                                                                                                                                                                                                                                                  int keyBlockEnd)

Method Detail

isGarbagePage

public boolean isGarbagePage()

Indicates whether the page occupying this buffer is a Garbage page.

Returns:

true if this is a Garbage page, otherwise false.

isDataPage

public boolean isDataPage()

Indicates whether the page occupying this buffer is a Data page.

Returns:

true if this is a Data page, otherwise false.

isIndexPage

public boolean isIndexPage()

Indicates whether the page occupying this buffer is an Index page.

Returns:

true if this is an Index page, otherwise false.

isLongRecordPage

public boolean isLongRecordPage()

Indicates whether the page occupying this buffer is a LongRecord page.

Returns:

true if this is a LongRecord page, otherwise false.

isUnallocatedPage

public boolean isUnallocatedPage()

Indicates whether the page occupying this buffer is an Unallocated page.

Returns:

true if this is an Unallocated page, otherwise false.

getPoolIndex

public int getPoolIndex()

Return the index of this Buffer within the BufferPool array.

Returns:

The index

getType

public int getType()

Return the type of page occupying this Buffer as an integer. See getTypeName() for a displayable form.

Returns:

The type.

getTypeName

public String getTypeName()

Return the type of page occupying this Buffer in displayable name form. Values include

 
    Unused
    Data
    IndexNN
    Garbage
    LongRecord
 
 

where NN indicates index level counting from the leaf data page.

Returns:

The displayable page type

getStatus

public int getStatus()

Return the status integer for this Buffer. See getStatusName() for a displayable form.

Returns:

The status integer.

getStatusName

public String getStatusName()

Return the status of this Buffer in displayable form. Character flags in the string value include:

   v - valid
   r - reader claim
   w - writer claim
   d - dirty
   nnn - count of threads with reader claims
 

Returns:

The status in displayable form

getWriterThreadName

public String getWriterThreadName()

Return the name of the Thread that currently holds a writer (exclusive) claim on the Buffer if there is one, otherwise returns null.

Returns:

The thread name, or null if there is none

getPageAddress

public long getPageAddress()

Returns:

The page address.

getRightSiblingAddress

public long getRightSiblingAddress()

Returns:

The page address of the right sibling page.

getVolumeName

public String getVolumeName()

Returns:

the Volume Name

getVolumeId

public long getVolumeId()

Returns:

the volume ID

getTimestamp

public long getTimestamp()

Returns:

the timestamp at which the page occupying this buffer was last changed.

getBufferSize

public int getBufferSize()

Returns:

the buffer size, in bytes

getAvailableBytes

public int getAvailableBytes()

Returns:

the number of unused bytes available to hold additional key/value pairs.

getAlloc

public int getAlloc()

Returns:

he offset within the Buffer used internally in allocating space for key/value pairs.

getSlack

public int getSlack()

Returns:

a size used internally in allocating space for key/value pairs.

getMvvCount

public int getMvvCount()

Returns:

the approximate count of key/value pairs containing multi-version values.

getMvvSize

public int getMvvSize()

Returns:

the approximate number of bytes consumed by multi-version values which are no longer visible to current transactions.

getKeyBlockStart

public int getKeyBlockStart()

Return an offset within the Buffer used internally in allocating space for key/value pairs.

Returns:

The keyBlockStart offset

getKeyBlockEnd

public int getKeyBlockEnd()

Return an offset within the Buffer used internally in allocating space for key/value pairs.

Returns:

The keyBlockEnd offset

displayableSummary

public String displayableSummary()

Return a human-readable summary of information about the page contained in this Buffer.

Returns:

a one-line displayable summary