org.apache.hadoop.fs.statistics

Interface IOStatisticsContext

All Superinterfaces:

IOStatisticsSource

All Known Implementing Classes:

IOStatisticsContextImpl

public interface IOStatisticsContext
extends IOStatisticsSource

An interface defined to capture thread-level IOStatistics by using per thread context.

The aggregator should be collected in their constructor by statistics-generating classes to obtain the aggregator to update across all threads.

The snapshot() call creates a snapshot of the statistics;

The reset() call resets the statistics in the context so that later snapshots will get the incremental data.

Method Summary

Modifier and Type	Method and Description
static boolean	enabled() Static probe to check if the thread-level IO statistics enabled.
IOStatisticsAggregator	getAggregator() Get the IOStatisticsAggregator for the context.
static IOStatisticsContext	getCurrentIOStatisticsContext() Get the context's IOStatisticsContext.
long	getID() Get a unique ID for this context, for logging purposes.
void	reset() Reset the context's IOStatistics.
static void	setThreadIOStatisticsContext(IOStatisticsContext statisticsContext) Set the IOStatisticsContext for the current thread.
IOStatisticsSnapshot	snapshot() Capture the snapshot of the context's IOStatistics.

Methods inherited from interface org.apache.hadoop.fs.statistics.IOStatisticsSource

getIOStatistics

Method Detail

getAggregator

IOStatisticsAggregator getAggregator()

Get the IOStatisticsAggregator for the context.

Returns:

return the aggregator for the context.

snapshot

IOStatisticsSnapshot snapshot()

Capture the snapshot of the context's IOStatistics.

Returns:

IOStatisticsSnapshot for the context.

getID

long getID()

Get a unique ID for this context, for logging purposes.

Returns:

an ID unique for all contexts in this process.

reset

void reset()

Reset the context's IOStatistics.

getCurrentIOStatisticsContext

static IOStatisticsContext getCurrentIOStatisticsContext()

Get the context's IOStatisticsContext.

Returns:

instance of IOStatisticsContext for the context.

setThreadIOStatisticsContext

static void setThreadIOStatisticsContext(IOStatisticsContext statisticsContext)

Set the IOStatisticsContext for the current thread.

Parameters:

statisticsContext - IOStatistics context instance for the current thread. If null, the context is reset.

enabled

static boolean enabled()

Static probe to check if the thread-level IO statistics enabled.

Returns:

if the thread-level IO statistics enabled.