Package com.bigdata.rdf.sparql.ast.hints

Query hints are specified at the SPARQL layer using magic predicates.

See: Description

Interface Summary

Interface	Description
IQueryHint<T>	Interface for declaring query hints.

Class Summary

Class	Description
AbstractBooleanQueryHint	Base class for Boolean query hints.
AbstractChunkSizeHint
AbstractQueryHint<T>	Base class for query hints.
AbstractStringQueryHint	Base class for String query hints.
BasicBooleanQueryHint	Basic boolean query hint.
BasicDoubleQueryHint	Basic double query hint.
BasicIntQueryHint	Basic integer query hint.
BasicLongQueryHint	Basic long integer query hint.
BasicStringQueryHint	Basic string query hint.
OptimizerQueryHint	The query hint governing the choice of the join order optimizer.
QueryHintRegistry	A factory which is used to register and resolve query hints.

Enum Summary

Enum	Description
QueryEngineChunkHandlerEnum	Type safe enumeration of known IChunkHandler implementations in support of the QueryEngineChunkHandlerQueryHint.
QueryHintScope	Type safe enumeration for the scope of a query hint.

Exception Summary

Exception	Description
QueryHintException	Exception thrown when a query hint is invalid/illegal.

Package com.bigdata.rdf.sparql.ast.hints Description

Query hints are specified at the SPARQL layer using magic predicates. A few special query hints are interpreted by the parser itself (currently only the QueryID). Most query hints are handled by the ASTQueryHintOptimizer.

Query hints wind up being handled in several different ways. Some of them cause query wide attributes to be set on the AST2BOpContext. Other query hints are transferred into ASTBase annotations and then subsequently intepreted either by other IASTOptimizers or by AST2BOpUtility. Finally, some query hints are set on the "queryHints" property of the ASTBase nodes. Those query hints are then transferred onto PipelineOps as they are generated.