Class ExecOpNaiveNestedLoopsJoin

java.lang.Object

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BinaryExecutableOpBase

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.ExecOpNaiveNestedLoopsJoin

All Implemented Interfaces:

StatsProvider, BinaryExecutableOp, ExecutableOperator

public class ExecOpNaiveNestedLoopsJoin
extends BinaryExecutableOpBase

Attention, this is a purely local implementation of the nested loops join algorithm---nothing fancy, no requests to federation members or anything. Instead, this algorithm first consumes the whole first input and materializes it into a list. Thereafter, it performs a local nested loops join in which the outer loop iterates over the second input and the inner loop (repeatedly) iterates over the list with the first input. It is certainly better to use the ExecOpHashJoin instead. Instead of simply putting all left-input solution mappings into a list, the hash join puts them into a hash index which can than be probed into for each right-input solution mapping.

Field Summary

Fields

Modifier and Type	Field	Description
protected final List<SolutionMapping>	inputLHS

Fields inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BinaryExecutableOpBase

timeAtCurrentLeftProcStart, timeAtCurrentRightProcStart

Fields inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

collectExceptions

Constructor Summary

Constructors

Constructor	Description
ExecOpNaiveNestedLoopsJoin(boolean collectExceptions)

Method Summary

Modifier and Type	Method	Description
protected void	_processInputFromChild1(SolutionMapping inputSolMap, IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to process the given solution mapping as input coming from the first operand and send the produced result elements (if any) to the given sink.
protected void	_processInputFromChild2(List<SolutionMapping> inputSolMaps, IntermediateResultElementSink sink, ExecutionContext execCxt)	Processes the input solution mappings of the given list by calling BinaryExecutableOpBase._processInputFromChild2(SolutionMapping, IntermediateResultElementSink, ExecutionContext) for each of them.
protected void	_processInputFromChild2(SolutionMapping inputSolMap, IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to process the given solution mapping as input coming from the second operand and send the produced result elements (if any) to the given sink.
protected void	_wrapUpForChild1(IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to finish up any processing related to the input coming from the first operand and send the remaining result elements (if any) to the given sink.
protected void	_wrapUpForChild2(IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to finish up any processing related to the input coming from the second operand and send the remaining result elements (if any) to the given sink.
boolean	requiresCompleteChild1InputFirst()	Returns true if this operator is implemented based on the assumption that the COMPLETE input from the first operand has been sent to it before input from the second operand is sent.

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BinaryExecutableOpBase

_processInputFromChild1, createStats, getStats, processInputFromChild1, processInputFromChild1, processInputFromChild2, processInputFromChild2, resetStats, wrapUpForChild1, wrapUpForChild2

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

getExceptionsCaughtDuringExecution, recordExceptionCaughtDuringExecution

Methods inherited from class java.lang.Object

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

Methods inherited from interface se.liu.ida.hefquin.engine.queryplan.executable.ExecutableOperator

getExceptionsCaughtDuringExecution

Field Details

inputLHS

protected final List<SolutionMapping> inputLHS

Constructor Details

ExecOpNaiveNestedLoopsJoin

public ExecOpNaiveNestedLoopsJoin(boolean collectExceptions)

Method Details

requiresCompleteChild1InputFirst

public boolean requiresCompleteChild1InputFirst()

Description copied from interface: BinaryExecutableOp

Returns true if this operator is implemented based on the assumption that the COMPLETE input from the first operand has been sent to it before input from the second operand is sent. An example of an operator that may return true here is a hash join (which first needs to add all result elements from the first operand into its hash table and, then, can start consuming the result elements from the second operand by probing into the hash table). In contrast, a symmetric hash join (which has two hash tables and can consume result elements from both inputs in any order) would return false. Operators that return true here may throw an IllegalStateException if their methods

invalid reference

#processBlockFromChild2(IntermediateResultBlock, IntermediateResultElementSink, ExecutionContext)

or BinaryExecutableOp.wrapUpForChild2(IntermediateResultElementSink, ExecutionContext) are called before BinaryExecutableOp.wrapUpForChild1(IntermediateResultElementSink, ExecutionContext) has been called.

_processInputFromChild1

protected void _processInputFromChild1(SolutionMapping inputSolMap,
 IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: BinaryExecutableOpBase

Implementations of this function need to process the given solution mapping as input coming from the first operand and send the produced result elements (if any) to the given sink. If an exception occurs while processing the solution mapping, then this exception needs to be thrown.

Specified by:

_processInputFromChild1 in class BinaryExecutableOpBase

_wrapUpForChild1

protected void _wrapUpForChild1(IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: BinaryExecutableOpBase

Implementations of this function need to finish up any processing related to the input coming from the first operand and send the remaining result elements (if any) to the given sink. If an exception occurs during this process, then this exception needs to be thrown.

Specified by:

_wrapUpForChild1 in class BinaryExecutableOpBase

_processInputFromChild2

protected void _processInputFromChild2(SolutionMapping inputSolMap,
 IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: BinaryExecutableOpBase

Implementations of this function need to process the given solution mapping as input coming from the second operand and send the produced result elements (if any) to the given sink. If an exception occurs while processing the solution mapping, then this exception needs to be thrown. May throw an IllegalStateException for operators for which BinaryExecutableOp.requiresCompleteChild1InputFirst() returns true and BinaryExecutableOpBase._wrapUpForChild1(IntermediateResultElementSink, ExecutionContext) has not been called yet.

Specified by:

_processInputFromChild2 in class BinaryExecutableOpBase

_processInputFromChild2

protected void _processInputFromChild2(List<SolutionMapping> inputSolMaps,
 IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: BinaryExecutableOpBase

Processes the input solution mappings of the given list by calling BinaryExecutableOpBase._processInputFromChild2(SolutionMapping, IntermediateResultElementSink, ExecutionContext) for each of them. Subclasses may override this behavior to send a greater number of output solution mappings to the given sink at a time (which is useful to reduce the communication between threads in the push-based execution model). If an exception occurs within the overriding implementation, then this exception needs to be thrown.

Overrides:

_processInputFromChild2 in class BinaryExecutableOpBase

_wrapUpForChild2

protected void _wrapUpForChild2(IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: BinaryExecutableOpBase

Implementations of this function need to finish up any processing related to the input coming from the second operand and send the remaining result elements (if any) to the given sink. If an exception occurs during this process, then this exception needs to be thrown. May throw an IllegalStateException for operators for which BinaryExecutableOp.requiresCompleteChild1InputFirst() returns true and BinaryExecutableOpBase._wrapUpForChild1(IntermediateResultElementSink, ExecutionContext) has not been called yet.

Specified by:

_wrapUpForChild2 in class BinaryExecutableOpBase