Package org.eclipse.rdf4j.repository.sail

Class SailQuery

java.lang.Object

org.eclipse.rdf4j.query.impl.AbstractOperation

org.eclipse.rdf4j.query.impl.AbstractQuery

org.eclipse.rdf4j.query.impl.AbstractParserQuery

org.eclipse.rdf4j.repository.sail.SailQuery

All Implemented Interfaces:

Operation, Query

Direct Known Subclasses:

SailBooleanQuery, SailGraphQuery, SailTupleQuery

public abstract class SailQuery
extends AbstractParserQuery

Author:

Arjohn Kampman

Nested Class Summary

Nested classes/interfaces inherited from interface org.eclipse.rdf4j.query.Query

Query.QueryType

Field Summary

Fields inherited from class org.eclipse.rdf4j.query.impl.AbstractParserQuery

DEFAULT_EXPLANATION_EXECUTION_TIMEOUT

Fields inherited from class org.eclipse.rdf4j.query.impl.AbstractOperation

bindings, dataset, includeInferred

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SailQuery(ParsedQuery parsedQuery, SailRepositoryConnection con)

Method Summary

Modifier and Type	Method	Description
Explanation	explain(Explanation.Level level)	Explain how the query will be (or has been) executed/evaluated by returning an explanation of the query plan.
protected SailRepositoryConnection	getConnection()

Methods inherited from class org.eclipse.rdf4j.query.impl.AbstractParserQuery

enforceMaxQueryTime, equals, getActiveDataset, getParsedQuery, hashCode, toString

Methods inherited from class org.eclipse.rdf4j.query.impl.AbstractQuery

getMaxQueryTime, setMaxQueryTime

Methods inherited from class org.eclipse.rdf4j.query.impl.AbstractOperation

clearBindings, getBindings, getDataset, getIncludeInferred, getMaxExecutionTime, removeBinding, setBinding, setDataset, setIncludeInferred, setMaxExecutionTime

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.rdf4j.query.Operation

clearBindings, getBindings, getDataset, getIncludeInferred, getMaxExecutionTime, removeBinding, setBinding, setDataset, setIncludeInferred, setMaxExecutionTime

Constructor Details

SailQuery

protected SailQuery(ParsedQuery parsedQuery,
 SailRepositoryConnection con)

Method Details

getConnection

protected SailRepositoryConnection getConnection()

explain

public Explanation explain(Explanation.Level level)

Description copied from interface: Query

Explain how the query will be (or has been) executed/evaluated by returning an explanation of the query plan.

This method is useful for understanding why a particular query is slow. The most useful level is Executed, but this takes as long as it takes to execute/evaluate the query.

When timing a query you should keep in mind that the query performance will vary based on how much the JIT compiler has compiled the code (C1 vs C2) and based on what is or isn't cached in memory. If Timed explanations are considerably slower than Executed explanations the overhead with timing the query may be large on your system and should not be trusted.

WARNING: This method is experimental and is subject to change or removal without warning. Same goes for the returned explanation. There is currently only partial support for this method in RDF4J and and UnsupportedOperationException where support is lacking.

Parameters:

level - The explanation level that should be used to create the explanation. Choose between: Unoptimized (as parsed without optimizations) , Optimized (as is actually going to be used), Executed (as was executed/evaluated, including some real performance metrics), Timed (as was executed/evaluated including all real performance metrics). Executed and Timed level can potentially be slow.

Returns:

The explanation that we generated, which can be viewed in a human readable format with toString(), as JSON or as a simplified query plan object structure.