org.apache.pig.impl.builtin

Class GetMemNumRows

java.lang.Object

org.apache.pig.EvalFunc<Tuple>

org.apache.pig.impl.builtin.GetMemNumRows

public class GetMemNumRows
extends EvalFunc<Tuple>

UDF to get memory size of a tuple and extracts number of rows value from special tuple created by PoissonSampleLoader It is used by skewed join.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.pig.EvalFunc

EvalFunc.SchemaType

Field Summary

Fields inherited from class org.apache.pig.EvalFunc

log, pigLogger, reporter, returnType

Constructor Summary

Constructors

Constructor and Description
GetMemNumRows()

Method Summary

Modifier and Type	Method and Description
Tuple	exec(Tuple in) This callback method must be implemented by all subclasses.
Type	getReturnType() Get the Type that this EvalFunc returns.

Methods inherited from class org.apache.pig.EvalFunc

allowCompileTimeCalculation, finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLoadCaster, getLogger, getPigLogger, getReporter, getSchemaName, getSchemaType, getShipFiles, isAsynchronous, needEndOfAllInputProcessing, outputSchema, progress, setEndOfAllInput, setInputSchema, setPigLogger, setReporter, setUDFContextSignature, warn

Methods inherited from class java.lang.Object

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

Constructor Detail

GetMemNumRows

public GetMemNumRows()

Method Detail

exec

public Tuple exec(Tuple in)
           throws IOException

Description copied from class: EvalFunc

This callback method must be implemented by all subclasses. This is the method that will be invoked on every Tuple of a given dataset. Since the dataset may be divided up in a variety of ways the programmer should not make assumptions about state that is maintained between invocations of this method.

Specified by:

exec in class EvalFunc<Tuple>

Parameters:

in - - input tuple

Returns:

- tuple having size in memory of this tuple and numRows if this is specially marked tuple having number of rows field

Throws:

IOException

getReturnType

public Type getReturnType()

Description copied from class: EvalFunc

Get the Type that this EvalFunc returns.

Overrides:

getReturnType in class EvalFunc<Tuple>

Returns:

Type