com.persistit

Class Management.BufferPoolInfo

java.lang.Object

com.persistit.Management.AcquisitionTimeBase

com.persistit.Management.BufferPoolInfo

All Implemented Interfaces:

Serializable

Enclosing interface:

Management

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

Exposes information about a BufferPool. A BufferPool is a container for all the buffers of a particular size. The Management.getBufferPoolInfoArray() method returns an array containing BufferPoolInfo elements for each buffer size.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static long	serialVersionUID

Constructor Summary

Constructors

Constructor and Description
BufferPoolInfo()
BufferPoolInfo(int bufferSize, int bufferCount, long missCount, long hitCount, long newCount, long writeCount, long evictCount, long forcedWriteCount, long forcedCheckpointWriteCount, long readCounter, int validPageCount, int dirtyPageCount, int readerClaimedPageCount, int writerClaimedPageCount, long earliestDirtyTimestamp)

Method Summary

Modifier and Type	Method and Description
int	getBufferCount() Return the count of Buffers managed by this pool.
int	getBufferSize() Return the size of Buffers managed by this pool.
int	getDirtyPageCount() Get the count of dirty pages (pages that contain updates not yet written to disk) in this pool.
long	getEarliestDirtyTimestamp()
long	getEvictCount() Return the count of valid pages evicted from this pool.
long	getForcedCheckpointWriteCount() Return count of pages forced to be written due to an updated after a checkpoint
long	getForcedWriteCount() Return count of pages forced to be written when dirty on eviction
long	getHitCount() Return the count of lookup operations for pages images in this pool for which the page image was already found in this BufferPool.
double	getHitRatio() Get the "hit ratio" - the number of hits divided by the number of overall gets.
long	getMissCount() Return the count of lookup operations for pages images in this pool.
long	getNewCount() Return the count of newly create pages images in this Pool.
int	getReaderClaimedPageCount() Get the count of pages on which running threads have reader (non-exclusive), but not writer (exclusive) claims in this pool.
int	getValidPageCount() Get the count of valid pages in this pool.
long	getWriteCount() Return count of pages written from this pool.
int	getWriterClaimedPageCount() Get the count of pages on which running threads have writer (exclusive) claims in this pool.

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

BufferPoolInfo

public BufferPoolInfo()

BufferPoolInfo

@ConstructorProperties(value={"bufferSize","bufferCount","missCount","hitCount","newCount","evictCount","writeCount","forcedWriteCount","forcedCheckpointWriteCount","validPageCount","dirtyPageCount","readerClaimedPageCount","writerClaimedPageCount","earliestDirtyTimestamp"})
public BufferPoolInfo(int bufferSize,
                                                                                                                                                                                                                                                                                                          int bufferCount,
                                                                                                                                                                                                                                                                                                          long missCount,
                                                                                                                                                                                                                                                                                                          long hitCount,
                                                                                                                                                                                                                                                                                                          long newCount,
                                                                                                                                                                                                                                                                                                          long writeCount,
                                                                                                                                                                                                                                                                                                          long evictCount,
                                                                                                                                                                                                                                                                                                          long forcedWriteCount,
                                                                                                                                                                                                                                                                                                          long forcedCheckpointWriteCount,
                                                                                                                                                                                                                                                                                                          long readCounter,
                                                                                                                                                                                                                                                                                                          int validPageCount,
                                                                                                                                                                                                                                                                                                          int dirtyPageCount,
                                                                                                                                                                                                                                                                                                          int readerClaimedPageCount,
                                                                                                                                                                                                                                                                                                          int writerClaimedPageCount,
                                                                                                                                                                                                                                                                                                          long earliestDirtyTimestamp)

Method Detail

getBufferSize

public int getBufferSize()

Return the size of Buffers managed by this pool.

Returns:

The size in bytes of each buffer in this pool

getBufferCount

public int getBufferCount()

Return the count of Buffers managed by this pool.

Returns:

The count

getMissCount

public long getMissCount()

Return the count of lookup operations for pages images in this pool. This number, in comparison with the hit counter, indicates how effective the cache is in reducing disk I/O.

Returns:

The get count

getHitCount

public long getHitCount()

Return the count of lookup operations for pages images in this pool for which the page image was already found in this BufferPool. This number, in comparison with the miss counter, indicates how effective the cache is in reducing disk I/O.

Returns:

The hit count

getNewCount

public long getNewCount()

Return the count of newly create pages images in this Pool. A new page is one that does not need to be read from disk.

Returns:

The new page counter

getEvictCount

public long getEvictCount()

Return the count of valid pages evicted from this pool.

Returns:

The evicted page count

getWriteCount

public long getWriteCount()

Return count of pages written from this pool.

Returns:

The forced write count

getForcedWriteCount

public long getForcedWriteCount()

Return count of pages forced to be written when dirty on eviction

Returns:

The forced write count

getForcedCheckpointWriteCount

public long getForcedCheckpointWriteCount()

Return count of pages forced to be written due to an updated after a checkpoint

Returns:

The forced checkpoint write count

getHitRatio

public double getHitRatio()

Get the "hit ratio" - the number of hits divided by the number of overall gets. A value close to 1.0 indicates that most attempts to find data in the BufferPool are successful - i.e., that the cache is effectively reducing the need for disk read operations.

Returns:

The ratio

getValidPageCount

public int getValidPageCount()

Get the count of valid pages in this pool.

Returns:

The count of valid pages in this pool

getDirtyPageCount

public int getDirtyPageCount()

Get the count of dirty pages (pages that contain updates not yet written to disk) in this pool.

Returns:

The count of dirty pages in this pool

getReaderClaimedPageCount

public int getReaderClaimedPageCount()

Get the count of pages on which running threads have reader (non-exclusive), but not writer (exclusive) claims in this pool.

Returns:

The count of pages with reader claims

getWriterClaimedPageCount

public int getWriterClaimedPageCount()

Get the count of pages on which running threads have writer (exclusive) claims in this pool.

Returns:

The count of pages with writer claims

getEarliestDirtyTimestamp

public long getEarliestDirtyTimestamp()

Returns:

Earliest timestamp of any dirty page in this BufferPool