Class LeviathanQueryOptions

A class encapsulating run-time options that can be configured for a LeviathanQueryProcessor.

Inheritance

object

LeviathanQueryOptions

LeviathanUpdateOptions

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: VDS.RDF.Query

Assembly: dotNetRdf.dll

Syntax

public class LeviathanQueryOptions

Properties

AlgebraOptimisation

Gets/Sets whether Algebra Optimization should be used.

Declaration

public bool AlgebraOptimisation { get; set; }

Property Value

Type	Description
bool

AlgebraOptimisers

Gets/Sets the optimisers to apply if AlgebraOptimisation is enabled.

Declaration

public IEnumerable<IAlgebraOptimiser> AlgebraOptimisers { get; set; }

Property Value

Type	Description
IEnumerable<IAlgebraOptimiser>

Describer

Gets/Sets the ISparqlDescribe which provides the Describe algorithm you wish to use.

Declaration

public ISparqlDescribe Describer { get; set; }

Property Value

Type	Description
ISparqlDescribe

Remarks

By default this will be the ConciseBoundedDescription (CBD) algorithm.

NodeComparer

Get or set the node comparer to use in evaluation.

Declaration

public ISparqlNodeComparer NodeComparer { get; set; }

Property Value

Type	Description
ISparqlNodeComparer

Remarks

You may want to provide a SparqlNodeComparer instance to specify a different culture or compare options for string comparison.

QueryExecutionTimeout

Gets/Sets the Hard Timeout limit for SPARQL Query Execution (in milliseconds).

Declaration

public long QueryExecutionTimeout { get; set; }

Property Value

Type	Description
long

Remarks

This is used to stop SPARQL queries running away and never completing execution, it defaults to 3 mins (180,000 milliseconds).

RigorousEvaluation

Gets/Sets whether to use rigorous query evaluation.

Declaration

public bool RigorousEvaluation { get; set; }

Property Value

Type	Description
bool

Remarks

Rigorous Query evaluation applies more checks to the triples produced by datasets to ensure they actually match the patterns being scanned. If the underlying index structures are able to guarantee this then rigorous evaluation may be turned off for faster evaluation which it is by default since our default TreeIndexedTripleCollection and TripleCollection implementations will guarantee this.

SparqlResultFactory

Gets/Sets the ISparqlResultFactory which creates the ISparqlResult instances that are passed to a ISparqlResultsHandler.

Declaration

public ISparqlResultFactory SparqlResultFactory { get; set; }

Property Value

Type	Description
ISparqlResultFactory

StrictOperators

Gets/Sets whether to use strict operators.

Declaration

public bool StrictOperators { get; set; }

Property Value

Type	Description
bool

Remarks

Strict Operators refers to the interpretation of certain operators like + and - in SPARQL expression evaluation. If enabled then the operators will function only as specified in the SPARQL specification. If disabled (which is the default) then certain extensions (which the SPARQL specification allows an implementation to provide) will be allowed e.g. date time arithmetic.

The only time you may want to disable this is if you are developing queries locally which you want to ensure are portable to other systems or when running the SPARQL compliance tests.

UriFactory

Gets/Sets the URI factory to use during query evaluation.

Declaration

public IUriFactory UriFactory { get; set; }

Property Value

Type	Description
IUriFactory

Remarks

When querying an in-memory dataset, using the same URI factory as the graphs being queried, or a child of the URI factor of the graphs being queried will save memory.

UsePLinqEvaluation

Gets/Sets whether the query engine will try to use PLinq where applicable to evaluate suitable SPARQL constructs in parallel.

Declaration

public bool UsePLinqEvaluation { get; set; }

Property Value

Type	Description
bool

Remarks

Defaults to true.

Extension Methods

Extensions.ToSafeString(object)

Extensions.AsEnumerable<T>(T)