org.apache.hadoop.hbase.coprocessor

Interface RegionCoprocessorEnvironment

All Superinterfaces:

CoprocessorEnvironment<RegionCoprocessor>

@InterfaceAudience.LimitedPrivate(value="Coprocesssor")
 @InterfaceStability.Evolving
public interface RegionCoprocessorEnvironment
extends CoprocessorEnvironment<RegionCoprocessor>

Method Summary

Modifier and Type	Method and Description
Connection	getConnection() Be careful RPC'ing from a Coprocessor context.
MetricRegistry	getMetricRegistryForRegionServer() Returns a MetricRegistry that can be used to track metrics at the region server level.
OnlineRegions	getOnlineRegions()
Region	getRegion()
RegionInfo	getRegionInfo()
ServerName	getServerName()
ConcurrentMap<String,Object>	getSharedData()

Methods inherited from interface org.apache.hadoop.hbase.CoprocessorEnvironment

getClassLoader, getConfiguration, getHBaseVersion, getInstance, getLoadSequence, getPriority, getVersion, shutdown, startup

Method Detail

getRegion

Region getRegion()

Returns:

the region associated with this coprocessor

getRegionInfo

RegionInfo getRegionInfo()

Returns:

region information for the region this coprocessor is running on

getOnlineRegions

OnlineRegions getOnlineRegions()

Returns:

Interface to Map of regions online on this RegionServer getServerName()}.

getSharedData

ConcurrentMap<String,Object> getSharedData()

Returns:

shared data between all instances of this coprocessor

getServerName

ServerName getServerName()

Returns:

Hosting Server's ServerName

getConnection

Connection getConnection()

Be careful RPC'ing from a Coprocessor context. RPC's will fail, stall, retry, and/or crawl because the remote side is not online, is struggling or it is on the other side of a network partition. Any use of Connection from inside a Coprocessor must be able to handle all such hiccups.

Using a Connection to get at a local resource -- say a Region that is on the local Server or using Admin Interface from a Coprocessor hosted on the Master -- will result in a short-circuit of the RPC framework to make a direct invocation avoiding RPC (and protobuf marshalling/unmarshalling).

Returns:

The host's Connection to the Cluster.

getMetricRegistryForRegionServer

MetricRegistry getMetricRegistryForRegionServer()

Returns a MetricRegistry that can be used to track metrics at the region server level. All metrics tracked at this level will be shared by all the coprocessor instances of the same class in the same region server process. Note that there will be one region coprocessor environment per region in the server, but all of these instances will share the same MetricRegistry. The metric instances (like Counter, Timer, etc) will also be shared among all of the region coprocessor instances.

See ExampleRegionObserverWithMetrics class in the hbase-examples modules to see examples of how metrics can be instantiated and used.

Returns:

A MetricRegistry for the coprocessor class to track and export metrics.