Class PhysicalOpHashJoin2

java.lang.Object

se.liu.ida.hefquin.engine.queryplan.physical.impl.BaseForPhysicalOpBinaryJoin

se.liu.ida.hefquin.engine.queryplan.physical.impl.PhysicalOpHashJoin2

All Implemented Interfaces:

QueryPlanOperator, BinaryPhysicalOp, BinaryPhysicalOpForLogicalOp, PhysicalOperator, PhysicalOperatorForLogicalOperator

public class PhysicalOpHashJoin2
extends BaseForPhysicalOpBinaryJoin

A physical operator that implements the hash join algorithm to perform a join of two sequences of input solution mappings (produced by the two sub-plans under this operator). The algorithm builds a hash table with the solution mappings of the second input sequence (using the values that they have for the join variables to decide where to place them in the hash table) and, thereafter, probes the hash table to find join partners for each of the solution mappings of the first input sequence.

The actual algorithm of this operator is implemented in the ExecOpHashJoin2 class.

In addition to this class, we also have PhysicalOpHashJoin1 which does essentially the same thing but builds the has table over the first input. However, in contrast to this class, that other one does not support outer-join semantics.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	PhysicalOpHashJoin2.Factory

Field Summary

Fields

Modifier and Type	Field	Description
protected static final PhysicalOpHashJoin2.Factory	factory

Fields inherited from class se.liu.ida.hefquin.engine.queryplan.physical.impl.BaseForPhysicalOpBinaryJoin

mayReduce, useOuterJoinSemantics

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PhysicalOpHashJoin2(boolean useOuterJoinSemantics, boolean mayReduce)

Method Summary

Modifier and Type	Method	Description
BinaryExecutableOp	createExecOp(boolean collectExceptions, QueryPlanningInfo qpInfo, ExpectedVariables... inputVars)	Creates and returns the executable operator to be used for this physical operator.
boolean	equals(Object o)
static PhysicalOpFactory	getFactory()
static PhysicalOpHashJoin2	getInstanceForInnerJoin(boolean mayReduce)
static PhysicalOpHashJoin2	getInstanceForOuterJoin(boolean mayReduce)
int	hashCode()
String	toString()
void	visit(PhysicalPlanVisitor visitor)

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.physical.impl.BaseForPhysicalOpBinaryJoin

getLogicalOperator

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface se.liu.ida.hefquin.engine.queryplan.physical.PhysicalOperatorForLogicalOperator

getExpectedVariables

Field Details

factory

protected static final PhysicalOpHashJoin2.Factory factory

Constructor Details

PhysicalOpHashJoin2

protected PhysicalOpHashJoin2(boolean useOuterJoinSemantics,
 boolean mayReduce)

Method Details

getFactory

public static PhysicalOpFactory getFactory()

createExecOp

public BinaryExecutableOp createExecOp(boolean collectExceptions,
 QueryPlanningInfo qpInfo,
 ExpectedVariables... inputVars)

Description copied from interface: PhysicalOperator

Creates and returns the executable operator to be used for this physical operator. The implementation of this method has to create a new ExecutableOperator object each time it is called. The given QueryPlanningInfo object is passed to the created executable operator (to be available via the ExecutableOperator.getQueryPlanningInfo() method) and should be taken from the physical plan whose root operator is this physical operator. The given collectExceptions flag is passed to the executable operator and determines whether that operator collects its exceptions (see ExecutableOperator.getExceptionsCaughtDuringExecution()) or throws them immediately. The number of ExpectedVariables objects passed as arguments to this method must be in line with the degree of this operator (e.g., for a unary operator, exactly one such object must be passed).

visit

public void visit(PhysicalPlanVisitor visitor)

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

getInstanceForInnerJoin

public static PhysicalOpHashJoin2 getInstanceForInnerJoin(boolean mayReduce)

getInstanceForOuterJoin

public static PhysicalOpHashJoin2 getInstanceForOuterJoin(boolean mayReduce)