Package se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.cardinality

Class MinBasedCardinalityEstimationImpl

java.lang.Object

se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.cardinality.CardinalityEstimationImpl

se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.cardinality.MinBasedCardinalityEstimationImpl

All Implemented Interfaces:

CardinalityEstimation

public class MinBasedCardinalityEstimationImpl
extends CardinalityEstimationImpl

This class implements a cardinality estimation approach that relies on the cardinalities of subPlans. Specifically, for the join operator of two subPlans, the join cardinality is determined as the minimum of the cardinalities of its subPlans. In the case of a subPlan with Union as the root operator, the cardinality is estimated by summing the cardinalities of each subPlan. ( as outlined on page 1052 in the paper[1]). [1] Heling, Lars, and Maribel Acosta. "Federated SPARQL query processing over heterogeneous linked data fragments." Proceedings of the ACM Web Conference 2022.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	MinBasedCardinalityEstimationImpl.WorkerForJoin
protected class	MinBasedCardinalityEstimationImpl.WorkerForUnion

Nested classes/interfaces inherited from class se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.cardinality.CardinalityEstimationImpl

CardinalityEstimationImpl.WorkerForRequestOps, CardinalityEstimationImpl.WorkerForSubquery

Field Summary

Fields inherited from class se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.cardinality.CardinalityEstimationImpl

cache, fedAccessMgr, vsCardEstimator

Constructor Summary

Constructors

Constructor	Description
MinBasedCardinalityEstimationImpl(FederationAccessManager fedAccessMgr)
MinBasedCardinalityEstimationImpl(QueryProcContext ctxt)

Method Summary

Modifier and Type	Method	Description
CompletableFuture<Integer>	_initiateCardinalityEstimation(PhysicalPlan plan)

Methods inherited from class se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.cardinality.CardinalityEstimationImpl

initiateCardinalityEstimation

Methods inherited from class java.lang.Object

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

Constructor Details

MinBasedCardinalityEstimationImpl

public MinBasedCardinalityEstimationImpl(FederationAccessManager fedAccessMgr)

MinBasedCardinalityEstimationImpl

public MinBasedCardinalityEstimationImpl(QueryProcContext ctxt)

Method Details

_initiateCardinalityEstimation

public CompletableFuture<Integer> _initiateCardinalityEstimation(PhysicalPlan plan)

Overrides:

_initiateCardinalityEstimation in class CardinalityEstimationImpl