org.apache.hadoop.hive.llap.metrics

Class ReadWriteLockMetrics

java.lang.Object

org.apache.hadoop.hive.llap.metrics.ReadWriteLockMetrics

All Implemented Interfaces:

ReadWriteLock

public class ReadWriteLockMetrics
extends Object
implements ReadWriteLock

Wrapper around a read/write lock to collect the lock wait times. Instances of this wrapper class can be used to collect/accumulate the wai times around R/W locks. This is helpful if the source of a performance issue might be related to lock contention and you need to identify the actual locks. Instances of this class can be wrapped around any ReadWriteLock implementation.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ReadWriteLockMetrics.LockMetricInfo
static class	ReadWriteLockMetrics.MetricsComparator Helper class to compare two LockMetricSource instances.

Method Summary

Modifier and Type	Method and Description
static org.apache.hadoop.metrics2.MetricsSource	createLockMetricsSource(String label) Factory method for new metric collections.
static List<org.apache.hadoop.metrics2.MetricsSource>	getAllMetricsSources() Returns a list with all created MetricsSource instances for the R/W lock metrics.
Lock	readLock()
static ReadWriteLock	wrap(org.apache.hadoop.conf.Configuration conf, ReadWriteLock lock, org.apache.hadoop.metrics2.MetricsSource metrics) Wraps a ReadWriteLock into a monitored lock if required by configuration.
Lock	writeLock()

Methods inherited from class java.lang.Object

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

Method Detail

wrap

public static ReadWriteLock wrap(org.apache.hadoop.conf.Configuration conf,
                                 ReadWriteLock lock,
                                 org.apache.hadoop.metrics2.MetricsSource metrics)

Wraps a ReadWriteLock into a monitored lock if required by configuration. This helper is checking the hive.llap.lockmetrics.collect configuration option and wraps the passed in ReadWriteLock into a monitoring container if the option is set to true. Otherwise, the original (passed in) lock instance is returned unmodified.

Parameters:

conf - Configuration instance to check for LLAP conf options

lock - The ReadWriteLock to wrap for monitoring

metrics - The target container for locking metrics

See Also:

createLockMetricsSource(java.lang.String)

createLockMetricsSource

public static org.apache.hadoop.metrics2.MetricsSource createLockMetricsSource(String label)

Factory method for new metric collections. You can create and use a single MetricsSource collection for multiple R/W locks. This makes sense if several locks belong to a single group and you're then interested in the accumulated values for the whole group, rather than the single lock instance. The passed in label is supposed to identify the group uniquely.

Parameters:

label - The group identifier for lock statistics

getAllMetricsSources

public static List<org.apache.hadoop.metrics2.MetricsSource> getAllMetricsSources()

Returns a list with all created MetricsSource instances for the R/W lock metrics. The returned list contains the instances that were previously created via the createLockMetricsSource function.

Returns:

A list of all R/W lock based metrics sources

readLock

public Lock readLock()

Specified by:

readLock in interface ReadWriteLock

writeLock

public Lock writeLock()

Specified by:

writeLock in interface ReadWriteLock