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

Class PhysicalOpIndexNestedLoopsJoin

java.lang.Object

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

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

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

All Implemented Interfaces:

PhysicalOperator, PhysicalOperatorForLogicalOperator, UnaryPhysicalOp, UnaryPhysicalOpForLogicalOp

public class PhysicalOpIndexNestedLoopsJoin
extends BaseForPhysicalOpSingleInputJoin

A physical operator that implements a version of the index nested loops join algorithm where the federation member is used as an index to request join partners for the input solution mappings.

Semantics: This operator implements the logical operators gpAdd (see LogicalOpGPAdd) and gpOptAdd (see LogicalOpGPOptAdd). That is, for a given graph pattern, a federation member, and an input sequence of solution mappings (produced by the sub-plan under this operator), the operator produces the solutions resulting from the join (inner or left outer) between the input solutions and the solutions of evaluating the given graph pattern over the data of the federation member.

Algorithm description: The outer loop iterates over the sequence of input solution mappings. For each such solution mapping, join partners within the result of the given graph pattern over the data of the federation member are retrieved by using the federation member as a form of index. The inner loop then iterates over these join partners and merges them with the current input solution mapping from the outer loop. The retrieval of join partners is done by applying the current input solution mapping from the outer loop to the given graph pattern of the operator (i.e., substituting the join variables in the pattern by the values assigned in the current input solution mapping) and, then, performing a request with the graph pattern resulting from the substitution.

The actual algorithm of this operator is implemented in the following three classes, where each of them is specific to a different type of federation member.

• ExecOpIndexNestedLoopsJoinTPF
• ExecOpIndexNestedLoopsJoinBRTPF
• ExecOpIndexNestedLoopsJoinSPARQL

Field Summary

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

lop

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

id

Constructor Summary

Constructors

Constructor	Description
PhysicalOpIndexNestedLoopsJoin(LogicalOpBGPAdd lop)
PhysicalOpIndexNestedLoopsJoin(LogicalOpBGPOptAdd lop)
PhysicalOpIndexNestedLoopsJoin(LogicalOpGPAdd lop)
PhysicalOpIndexNestedLoopsJoin(LogicalOpGPOptAdd lop)
PhysicalOpIndexNestedLoopsJoin(LogicalOpTPAdd lop)
PhysicalOpIndexNestedLoopsJoin(LogicalOpTPOptAdd lop)

Method Summary

Modifier and Type	Method	Description
UnaryExecutableOp	createExecOp(boolean collectExceptions, ExpectedVariables... inputVars)	Creates and returns the executable operator to be used for this physical operator.
boolean	equals(Object o)
String	toString()
void	visit(PhysicalPlanVisitor visitor)

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

getExpectedVariables, getLogicalOperator, hashCode

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

getID

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.PhysicalOperator

getID

Constructor Details

PhysicalOpIndexNestedLoopsJoin

public PhysicalOpIndexNestedLoopsJoin(LogicalOpTPAdd lop)

PhysicalOpIndexNestedLoopsJoin

public PhysicalOpIndexNestedLoopsJoin(LogicalOpTPOptAdd lop)

PhysicalOpIndexNestedLoopsJoin

public PhysicalOpIndexNestedLoopsJoin(LogicalOpBGPAdd lop)

PhysicalOpIndexNestedLoopsJoin

public PhysicalOpIndexNestedLoopsJoin(LogicalOpBGPOptAdd lop)

PhysicalOpIndexNestedLoopsJoin

public PhysicalOpIndexNestedLoopsJoin(LogicalOpGPAdd lop)

PhysicalOpIndexNestedLoopsJoin

public PhysicalOpIndexNestedLoopsJoin(LogicalOpGPOptAdd lop)

Method Details

equals

public boolean equals(Object o)

Overrides:

equals in class BaseForPhysicalOpSingleInputJoin

createExecOp

public UnaryExecutableOp createExecOp(boolean collectExceptions,
 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 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)

toString

public String toString()

Overrides:

toString in class Object