org.apache.hadoop.hbase.coprocessor

Class AggregateImplementation<T,S,P extends Message,Q extends Message,R extends Message>

java.lang.Object

org.apache.hadoop.hbase.protobuf.generated.AggregateProtos.AggregateService

org.apache.hadoop.hbase.coprocessor.AggregateImplementation<T,S,P,Q,R>

All Implemented Interfaces:

Service, Coprocessor, RegionCoprocessor

@InterfaceAudience.Private
public class AggregateImplementation<T,S,P extends Message,Q extends Message,R extends Message>
extends AggregateProtos.AggregateService
implements RegionCoprocessor

A concrete AggregateProtocol implementation. Its system level coprocessor that computes the aggregate function at a region level. ColumnInterpreter is used to interpret column value. This class is parameterized with the following (these are the types with which the ColumnInterpreter is parameterized, and for more description on these, refer to ColumnInterpreter):

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.protobuf.generated.AggregateProtos.AggregateService

AggregateProtos.AggregateService.BlockingInterface, AggregateProtos.AggregateService.Interface, AggregateProtos.AggregateService.Stub

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.Coprocessor

Coprocessor.State

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.slf4j.Logger	log

Fields inherited from interface org.apache.hadoop.hbase.Coprocessor

PRIORITY_HIGHEST, PRIORITY_LOWEST, PRIORITY_SYSTEM, PRIORITY_USER, VERSION

Constructor Summary

Constructors

Constructor and Description
AggregateImplementation()

Method Summary

Modifier and Type	Method and Description
void	getAvg(RpcController controller, AggregateProtos.AggregateRequest request, RpcCallback<AggregateProtos.AggregateResponse> done) Gives a Pair with first object as Sum and second object as row count, computed for a given combination of column qualifier and column family in the given row range as defined in the Scan object.
void	getMax(RpcController controller, AggregateProtos.AggregateRequest request, RpcCallback<AggregateProtos.AggregateResponse> done) Gives the maximum for a given combination of column qualifier and column family, in the given row range as defined in the Scan object.
void	getMedian(RpcController controller, AggregateProtos.AggregateRequest request, RpcCallback<AggregateProtos.AggregateResponse> done) Gives a List containing sum of values and sum of weights.
void	getMin(RpcController controller, AggregateProtos.AggregateRequest request, RpcCallback<AggregateProtos.AggregateResponse> done) Gives the minimum for a given combination of column qualifier and column family, in the given row range as defined in the Scan object.
void	getRowNum(RpcController controller, AggregateProtos.AggregateRequest request, RpcCallback<AggregateProtos.AggregateResponse> done) Gives the row count for the given column family and column qualifier, in the given row range as defined in the Scan object.
Iterable<Service>	getServices()
void	getStd(RpcController controller, AggregateProtos.AggregateRequest request, RpcCallback<AggregateProtos.AggregateResponse> done) Gives a Pair with first object a List containing Sum and sum of squares, and the second object as row count.
void	getSum(RpcController controller, AggregateProtos.AggregateRequest request, RpcCallback<AggregateProtos.AggregateResponse> done) Gives the sum for a given combination of column qualifier and column family, in the given row range as defined in the Scan object.
void	start(CoprocessorEnvironment env) Stores a reference to the coprocessor environment provided by the RegionCoprocessorHost from the region where this coprocessor is loaded.
void	stop(CoprocessorEnvironment env)

Methods inherited from class org.apache.hadoop.hbase.protobuf.generated.AggregateProtos.AggregateService

callMethod, getDescriptor, getDescriptorForType, getRequestPrototype, getResponsePrototype, newBlockingStub, newReflectiveBlockingService, newReflectiveService, newStub

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.hbase.coprocessor.RegionCoprocessor

getBulkLoadObserver, getEndpointObserver, getRegionObserver

Field Detail

log

protected static final org.slf4j.Logger log

Constructor Detail

AggregateImplementation

public AggregateImplementation()

Method Detail

getMax

public void getMax(RpcController controller,
                   AggregateProtos.AggregateRequest request,
                   RpcCallback<AggregateProtos.AggregateResponse> done)

Gives the maximum for a given combination of column qualifier and column family, in the given row range as defined in the Scan object. In its current implementation, it takes one column family and one column qualifier (if provided). In case of null column qualifier, maximum value for the entire column family will be returned.

Specified by:

getMax in class AggregateProtos.AggregateService

getMin

public void getMin(RpcController controller,
                   AggregateProtos.AggregateRequest request,
                   RpcCallback<AggregateProtos.AggregateResponse> done)

Gives the minimum for a given combination of column qualifier and column family, in the given row range as defined in the Scan object. In its current implementation, it takes one column family and one column qualifier (if provided). In case of null column qualifier, minimum value for the entire column family will be returned.

Specified by:

getMin in class AggregateProtos.AggregateService

getSum

public void getSum(RpcController controller,
                   AggregateProtos.AggregateRequest request,
                   RpcCallback<AggregateProtos.AggregateResponse> done)

Gives the sum for a given combination of column qualifier and column family, in the given row range as defined in the Scan object. In its current implementation, it takes one column family and one column qualifier (if provided). In case of null column qualifier, sum for the entire column family will be returned.

Specified by:

getSum in class AggregateProtos.AggregateService

getRowNum

public void getRowNum(RpcController controller,
                      AggregateProtos.AggregateRequest request,
                      RpcCallback<AggregateProtos.AggregateResponse> done)

Gives the row count for the given column family and column qualifier, in the given row range as defined in the Scan object.

Specified by:

getRowNum in class AggregateProtos.AggregateService

getAvg

public void getAvg(RpcController controller,
                   AggregateProtos.AggregateRequest request,
                   RpcCallback<AggregateProtos.AggregateResponse> done)

Gives a Pair with first object as Sum and second object as row count, computed for a given combination of column qualifier and column family in the given row range as defined in the Scan object. In its current implementation, it takes one column family and one column qualifier (if provided). In case of null column qualifier, an aggregate sum over all the entire column family will be returned.

The average is computed in AggregationClient#avg(byte[], ColumnInterpreter, Scan) by processing results from all regions, so its "ok" to pass sum and a Long type.

Specified by:

getAvg in class AggregateProtos.AggregateService

getStd

public void getStd(RpcController controller,
                   AggregateProtos.AggregateRequest request,
                   RpcCallback<AggregateProtos.AggregateResponse> done)

Gives a Pair with first object a List containing Sum and sum of squares, and the second object as row count. It is computed for a given combination of column qualifier and column family in the given row range as defined in the Scan object. In its current implementation, it takes one column family and one column qualifier (if provided). The idea is get the value of variance first: the average of the squares less the square of the average a standard deviation is square root of variance.

Specified by:

getStd in class AggregateProtos.AggregateService

getMedian

public void getMedian(RpcController controller,
                      AggregateProtos.AggregateRequest request,
                      RpcCallback<AggregateProtos.AggregateResponse> done)

Gives a List containing sum of values and sum of weights. It is computed for the combination of column family and column qualifier(s) in the given row range as defined in the Scan object. In its current implementation, it takes one column family and two column qualifiers. The first qualifier is for values column and the second qualifier (optional) is for weight column.

Specified by:

getMedian in class AggregateProtos.AggregateService

getServices

public Iterable<Service> getServices()

Specified by:

getServices in interface Coprocessor

start

public void start(CoprocessorEnvironment env)
           throws IOException

Stores a reference to the coprocessor environment provided by the RegionCoprocessorHost from the region where this coprocessor is loaded. Since this is a coprocessor endpoint, it always expects to be loaded on a table region, so always expects this to be an instance of RegionCoprocessorEnvironment.

Specified by:

start in interface Coprocessor

Parameters:

env - the environment provided by the coprocessor host

Throws:

IOException - if the provided environment is not an instance of RegionCoprocessorEnvironment

stop

public void stop(CoprocessorEnvironment env)
          throws IOException

Specified by:

stop in interface Coprocessor

Throws:

IOException