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https://issues.apache.org/jira/browse/GEODE-1494?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Dan Smith updated GEODE-1494:
-----------------------------
Description:
The Statistics interface has methods to increment, set, and get the value of
various statistics. The statistics are sampled at the sample-rate by the stat
sampling thread.
We should add a way to provide a callback that computes the value of the
statistic. The callback can be called by the stat sampling thread to compute
the value at the sample time.
This is useful because some statistics are hard to update correctly using using
increment operations. For example, tracking the total number of entries in a
parallel async event queue is tricky, because buckets may move on and off of a
node while concurrent operations are also adding entries. But measuring the
current size of the queue is easy by just calling size on the underlying
regions.
Here are the proposed new methods on the statistics interface:
{code}
/**
* Provide a callback to compute the value of this statistic
* every sample interval and use that as the value of the stat.
* <p>
* The callback should return quickly because it is invoked on a shared
thread.
* It should not do any expensive computations, network calls, or access any
resources
* under locks that may be locked by long running processes.
* <p>
* This callback will only be invoked if the distributed system property
* statistic-sampling-enabled is set to true, and it will be invoked at
intervals
* determined by the statistic-sampling-rate.
* <p>
* Get methods are not guaranteed to recompute a new value, they may return
* the last sampled value
* @param id a statistic id obtained with {@link #nameToId}
* or {@link StatisticsType#nameToId}.
* @param supplier a callback that will return the value of the stat. This
* replaces any previously registered supplier. If the passed in suppplier is
null, it
* will remove any existing supplier
* @return the previously registered supplier, or null if there was no
previously registered supplier
* @throws ArrayIndexOutOfBoundsException If the id is invalid.
* @throws IllegalArgumentException if the type of this
* stat is not int
*/
public IntSupplier setIntSupplier(int id, IntSupplier supplier);
public LongSupplier setLongSupplier(int id, LongSupplier supplier);
public DoubleSupplier setDoubleSupplier(int id, DoubleSupplier supplier);
public IntSupplier setIntSupplier(String name, IntSupplier supplier);
public LongSupplier setLongSupplier(String name, LongSupplier supplier);
public DoubleSupplier setDoubleSupplier(String name, DoubleSupplier supplier);
public IntSupplier setIntSupplier(StatisticDescriptor descriptor, IntSupplier
supplier);
public LongSupplier setLongSupplier(StatisticDescriptor descriptor,
LongSupplier supplier);
public DoubleSupplier setDoubleSupplier(StatisticDescriptor descriptor,
DoubleSupplier supplier);
{code}
was:
The Statistics interface has methods to increment, set, and get the value of
various statistics. The statistics are sampled at the sample-rate by the stat
sampling thread.
We should add a way to provide a callback that computes the value of the
statistic. The callback can be called by the stat sampling thread to compute
the value at the sample time.
This is useful because some statistics are hard to update correctly using using
increment operations. For example, tracking the total number of entries in a
parallel async event queue is tricky, because buckets may move on and off of a
node while concurrent operations are also adding entries. But measuring the
current size of the queue is easy by just calling size on the underlying
regions.
Here are the proposed new methods on the statistics interface:
{code}
/**
* Provide a callback to compute the value of this statistic
* every sample interval and use that as the value of the stat.
*
*/
public void sampleInt(int id, IntSupplier supplier);
public void sampleLong(int id, LongSupplier supplier);
public void sampleDouble(int id, DoubleSupplier supplier);
public void sampleInt(String name, IntSupplier supplier);
public void sampleLong(String name, LongSupplier supplier);
public void sampleDouble(String name, DoubleSupplier supplier);
public void sampleInt(StatisticDescriptor descriptor, IntSupplier supplier);
public void sampleLong(StatisticDescriptor descriptor, LongSupplier supplier);
public void sampleDouble(StatisticDescriptor descriptor, DoubleSupplier
supplier);
{code}
> Allow users to provide callbacks to sample statistics
> -----------------------------------------------------
>
> Key: GEODE-1494
> URL: https://issues.apache.org/jira/browse/GEODE-1494
> Project: Geode
> Issue Type: Improvement
> Reporter: Dan Smith
> Assignee: Dan Smith
>
> The Statistics interface has methods to increment, set, and get the value of
> various statistics. The statistics are sampled at the sample-rate by the stat
> sampling thread.
> We should add a way to provide a callback that computes the value of the
> statistic. The callback can be called by the stat sampling thread to compute
> the value at the sample time.
> This is useful because some statistics are hard to update correctly using
> using increment operations. For example, tracking the total number of entries
> in a parallel async event queue is tricky, because buckets may move on and
> off of a node while concurrent operations are also adding entries. But
> measuring the current size of the queue is easy by just calling size on the
> underlying regions.
> Here are the proposed new methods on the statistics interface:
> {code}
> /**
> * Provide a callback to compute the value of this statistic
> * every sample interval and use that as the value of the stat.
> * <p>
> * The callback should return quickly because it is invoked on a shared
> thread.
> * It should not do any expensive computations, network calls, or access
> any resources
> * under locks that may be locked by long running processes.
> * <p>
> * This callback will only be invoked if the distributed system property
> * statistic-sampling-enabled is set to true, and it will be invoked at
> intervals
> * determined by the statistic-sampling-rate.
> * <p>
> * Get methods are not guaranteed to recompute a new value, they may return
> * the last sampled value
> * @param id a statistic id obtained with {@link #nameToId}
> * or {@link StatisticsType#nameToId}.
> * @param supplier a callback that will return the value of the stat. This
> * replaces any previously registered supplier. If the passed in suppplier
> is null, it
> * will remove any existing supplier
> * @return the previously registered supplier, or null if there was no
> previously registered supplier
> * @throws ArrayIndexOutOfBoundsException If the id is invalid.
> * @throws IllegalArgumentException if the type of this
> * stat is not int
> */
> public IntSupplier setIntSupplier(int id, IntSupplier supplier);
> public LongSupplier setLongSupplier(int id, LongSupplier supplier);
> public DoubleSupplier setDoubleSupplier(int id, DoubleSupplier supplier);
> public IntSupplier setIntSupplier(String name, IntSupplier supplier);
> public LongSupplier setLongSupplier(String name, LongSupplier supplier);
> public DoubleSupplier setDoubleSupplier(String name, DoubleSupplier
> supplier);
> public IntSupplier setIntSupplier(StatisticDescriptor descriptor,
> IntSupplier supplier);
> public LongSupplier setLongSupplier(StatisticDescriptor descriptor,
> LongSupplier supplier);
> public DoubleSupplier setDoubleSupplier(StatisticDescriptor descriptor,
> DoubleSupplier supplier);
> {code}
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