com.bigdata.io.writecache

Class WriteCacheServiceCounters

java.lang.Object

com.bigdata.io.writecache.WriteCacheCounters

com.bigdata.io.writecache.WriteCacheServiceCounters

All Implemented Interfaces:

IWriteCacheCounters, IWriteCacheServiceCounters

public class WriteCacheServiceCounters
extends WriteCacheCounters
implements IWriteCacheServiceCounters

Performance counters for the WriteCacheService.

Author:

Bryan Thompson

Field Summary

Fields

Modifier and Type	Field and Description
int	compactingThreshold The threshold of reclaimable space at which we will attempt to coalesce records in cache buffers.
int	dirtyListThreshold The configured dirty list threshold before evicting to disk (immutable).
long	elapsedBufferEvictedToChannelNanos The cumulative latency (nanoseconds) when writing a write cache buffer onto the backing channel.
long	elapsedCacheWriteNanos The cumulative latency (nanoseconds) when writing into the write cache.
int	maxdirty The maximum #of dirty buffers observed by the WriteCacheService.WriteTask (its maximum observed backlog).
CAT	memoCacheSize
long	nbufferEvictedToChannel The #of WriteCache buffers written to the disk.
int	nbuffers #of configured buffers (immutable).
long	ncacheWrites The #of record-level writes made onto the WriteCacheService.
int	nclean #of clean buffers (instantaneous).
long	nclearAddrCleared The #of addresses actually found and cleared from the cache by the WriteCacheService.
long	nclearAddrRequests The requests to clear an address from the cache.
long	ncompact The #of WriteCache buffers that have been compacted.
int	ndirty #of dirty buffers (instantaneous).
CAT	nreadNotInstalled The #of read requests that were a miss in the cache and resulted in a read through to the disk where the record was NOT installed into the read cache (either because there is no read cache, because the record is too large for the read cache, or because the thread could not obtain a WriteCache.ReadCache block to install the read).
long	nrecordsEvictedToChannel The cumulative number of records written onto the backing channel.
long	nreset #of times the WriteCacheService was reset (typically to handle an error condition).
long	nsend The #of WriteCache blocks sent by the leader to the first downstream follower.

Fields inherited from class com.bigdata.io.writecache.WriteCacheCounters

bytesAccepted, bytesWritten, elapsedWriteNanos, naccept, nchannelWrite, nhit, nmiss

Fields inherited from interface com.bigdata.io.writecache.IWriteCacheServiceCounters

AVERAGE_BUFFER_EVICTED_TO_CHANNEL_NANOS, AVERAGE_CACHE_WRITE_NANOS, AVERAGE_RANDOM_WRITES_PER_SECOND, AVERAGE_RECORD_EVICTED_TO_CHANNEL_NANOS, COMPACTING_THRESHOLD, DIRTY_LIST_THRESHOLD, ELAPSED_BUFFER_EVICTED_TO_CHANNEL_NANOS, ELAPSED_CACHE_WRITES_NANOS, MAX_DIRTY, MB_PER_SEC, MEMO_CACHE_SIZE, NBUFFER_EVICTED_TO_CHANNEL, NBUFFERS, NCACHE_WRITES, NCLEAN, NCLEAR_ADDR_CLEARED, NCLEAR_ADDR_REQUESTS, NCOMPACT, NDIRTY, NREAD_NOT_INSTALLED, NRECORDS_EVICTED_TO_CHANNEL, NRESET, NSEND

Fields inherited from interface com.bigdata.io.writecache.IWriteCacheCounters

BYTES_ACCEPTED, BYTES_PER_WRITE, BYTES_WRITTEN, HIT_RATE, NACCEPT, NCHANNEL_WRITE, NHIT, NMISS, WRITE_SECS

Constructor Summary

Constructors

Constructor and Description
WriteCacheServiceCounters(int nbuffers, int dirtyListThreshold, int compactingThreshold)

Method Summary

Methods

Modifier and Type	Method and Description
CounterSet	getCounters()

Methods inherited from class com.bigdata.io.writecache.WriteCacheCounters

toString

Methods inherited from class java.lang.Object

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

Field Detail

nbuffers

public final int nbuffers

#of configured buffers (immutable).

dirtyListThreshold

public final int dirtyListThreshold

The configured dirty list threshold before evicting to disk (immutable).

compactingThreshold

public final int compactingThreshold

The threshold of reclaimable space at which we will attempt to coalesce records in cache buffers.

ndirty

public volatile int ndirty

#of dirty buffers (instantaneous).

Note: This is set by the WriteCacheService.WriteTask thread and by WriteCacheService.reset(). It is volatile so it is visible from a thread which looks at the counters and for correct publication from reset().

nclean

public volatile int nclean

#of clean buffers (instantaneous).

Note: This is set by the WriteCacheService.WriteTask thread and by WriteCacheService.reset(). It is volatile so it is visible from a thread which looks at the counters and for correct publication from reset().

maxdirty

public volatile int maxdirty

The maximum #of dirty buffers observed by the WriteCacheService.WriteTask (its maximum observed backlog). This is only set by the WriteCacheService.WriteTask thread, but it is volatile so it is visible from a thread which looks at the counters.

nreset

public volatile long nreset

#of times the WriteCacheService was reset (typically to handle an error condition).

Note: This is set by WriteCacheService.reset(). It is volatile so it is visible from a thread which looks at the counters and for correct publication from reset().

nsend

public volatile long nsend

The #of WriteCache blocks sent by the leader to the first downstream follower.

nbufferEvictedToChannel

public volatile long nbufferEvictedToChannel

The #of WriteCache buffers written to the disk.

elapsedBufferEvictedToChannelNanos

public volatile long elapsedBufferEvictedToChannelNanos

The cumulative latency (nanoseconds) when writing a write cache buffer onto the backing channel. See BLZG-1589 (new latency-oriented counters)

nrecordsEvictedToChannel

public volatile long nrecordsEvictedToChannel

The cumulative number of records written onto the backing channel. This may be used to track the number of induced write operators per second. However, note that the RWStore will pad out writes to their slot size in order to offer the underlying file system and disk controller an opportunity to meld together multiple writes into a single IO. This is particularly effective in combination with the small slots optimization. See BLZG-1589 (new latency-oriented counters)

ncompact

public volatile long ncompact

The #of WriteCache buffers that have been compacted.

ncacheWrites

public volatile long ncacheWrites

The #of record-level writes made onto the WriteCacheService.

elapsedCacheWriteNanos

public volatile long elapsedCacheWriteNanos

The cumulative latency (nanoseconds) when writing into the write cache. See BLZG-1589 (new latency-oriented counters)

nclearAddrRequests

public volatile long nclearAddrRequests

The requests to clear an address from the cache.

See Also:

WriteCacheService.clearWrite(long, int)

nclearAddrCleared

public volatile long nclearAddrCleared

The #of addresses actually found and cleared from the cache by the WriteCacheService.

See Also:

WriteCacheService.clearWrite(long, int)

nreadNotInstalled

public final CAT nreadNotInstalled

The #of read requests that were a miss in the cache and resulted in a read through to the disk where the record was NOT installed into the read cache (either because there is no read cache, because the record is too large for the read cache, or because the thread could not obtain a WriteCache.ReadCache block to install the read).

memoCacheSize

public final CAT memoCacheSize

Constructor Detail

WriteCacheServiceCounters

public WriteCacheServiceCounters(int nbuffers,
                         int dirtyListThreshold,
                         int compactingThreshold)

Method Detail

getCounters

public CounterSet getCounters()

Overrides:

getCounters in class WriteCacheCounters