org.neo4j.io.pagecache.tracing

Class DefaultPageCacheTracer

java.lang.Object

org.neo4j.io.pagecache.tracing.DefaultPageCacheTracer

All Implemented Interfaces:

PageCacheCounters, PageCacheTracer

public class DefaultPageCacheTracer
extends Object
implements PageCacheTracer

The default PageCacheTracer implementation, that just increments counters.

Field Summary

Fields inherited from interface org.neo4j.io.pagecache.tracing.PageCacheTracer

NULL

Constructor Summary

Constructors

Constructor and Description
DefaultPageCacheTracer()

Method Summary

Modifier and Type	Method and Description
MajorFlushEvent	beginCacheFlush() The PageCache wants to flush all its bound pages.
MajorFlushEvent	beginFileFlush(PageSwapper swapper) A PagedFile wants to flush all its bound pages.
EvictionRunEvent	beginPageEvictions(int pageCountToEvict) A background eviction has begun.
PinEvent	beginPin(boolean writeLock, long filePageId, PageSwapper swapper) A page is to be pinned.
long	bytesRead()
long	bytesWritten()
static void	enablePinUnpinTracing() Enable monitoring of page pins and unpins, which is disabled by default for performance reasons.
long	evictionExceptions()
long	evictions()
long	faults()
long	filesMapped()
long	filesUnmapped()
long	flushes()
void	mappedFile(File file) The given file has been mapped, where no existing mapping for that file existed.
long	pins()
void	unmappedFile(File file) The last reference to the given file has been unmapped.
long	unpins()

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultPageCacheTracer

public DefaultPageCacheTracer()

Method Detail

enablePinUnpinTracing

public static void enablePinUnpinTracing()

Enable monitoring of page pins and unpins, which is disabled by default for performance reasons. This is a one-way operation; once monitoring of pinning and unpinning has been enabled, it cannot be disabled again without restarting the JVM.

mappedFile

public void mappedFile(File file)

Description copied from interface: PageCacheTracer

The given file has been mapped, where no existing mapping for that file existed.

Specified by:

mappedFile in interface PageCacheTracer

unmappedFile

public void unmappedFile(File file)

Description copied from interface: PageCacheTracer

The last reference to the given file has been unmapped.

Specified by:

unmappedFile in interface PageCacheTracer

beginPageEvictions

public EvictionRunEvent beginPageEvictions(int pageCountToEvict)

Description copied from interface: PageCacheTracer

A background eviction has begun. Called from the background eviction thread. This call will be paired with a following PageCacheTracer#endPageEviction call. The method returns an EvictionRunEvent to represent the event of this eviction run.

Specified by:

beginPageEvictions in interface PageCacheTracer

beginPin

public PinEvent beginPin(boolean writeLock,
                         long filePageId,
                         PageSwapper swapper)

Description copied from interface: PageCacheTracer

A page is to be pinned.

Specified by:

beginPin in interface PageCacheTracer

beginFileFlush

public MajorFlushEvent beginFileFlush(PageSwapper swapper)

Description copied from interface: PageCacheTracer

A PagedFile wants to flush all its bound pages.

Specified by:

beginFileFlush in interface PageCacheTracer

beginCacheFlush

public MajorFlushEvent beginCacheFlush()

Description copied from interface: PageCacheTracer

The PageCache wants to flush all its bound pages.

Specified by:

beginCacheFlush in interface PageCacheTracer

faults

public long faults()

Specified by:

faults in interface PageCacheCounters

Returns:

The number of page faults observed thus far.

evictions

public long evictions()

Specified by:

evictions in interface PageCacheCounters

Returns:

The number of page evictions observed thus far.

pins

public long pins()

Specified by:

pins in interface PageCacheCounters

Returns:

The number of page pins observed thus far.

unpins

public long unpins()

Specified by:

unpins in interface PageCacheCounters

Returns:

The number of page unpins observed thus far.

flushes

public long flushes()

Specified by:

flushes in interface PageCacheCounters

Returns:

The number of page flushes observed thus far.

bytesRead

public long bytesRead()

Specified by:

bytesRead in interface PageCacheCounters

Returns:

The sum total of bytes read in through page faults thus far.

bytesWritten

public long bytesWritten()

Specified by:

bytesWritten in interface PageCacheCounters

Returns:

The sum total of bytes written through flushes thus far.

filesMapped

public long filesMapped()

Specified by:

filesMapped in interface PageCacheCounters

Returns:

The number of file mappings observed thus far.

filesUnmapped

public long filesUnmapped()

Specified by:

filesUnmapped in interface PageCacheCounters

Returns:

The number of file unmappings observed thus far.

evictionExceptions

public long evictionExceptions()

Specified by:

evictionExceptions in interface PageCacheCounters

Returns:

The number of page evictions that have thrown exceptions thus far.