public class HTreeDistinctBindingSetsOp extends PipelineOp implements ISingleThreadedOp
HTreesuitable for very large solution sets. Only the variables which are used to determine the DISTINCT solutions are projected from the operator. The operator is specific to the RDF data model (it relies on encoded
Note: This implementation is a single-threaded pipelined operator which inspects each chunk of solutions as they arrive and those solutions which are distinct for each chunk passed on.
PipelineOp.Annotations#MAX_MEMORY is currently ignored by this
operator. This value could be used to trigger the switch to an external
memory DISTINCT (on a backing store) or to fail a query which attempts to put
too much data into the native heap. Right now, it will just keep adding data
on the native heap and eventually the machine will begin to swap.
|Modifier and Type||Class and Description|
|Constructor and Description|
Required shallow copy constructor.
Constructor required for
|Modifier and Type||Method and Description|
assertAtOnceJavaHeapOp, assertMaxParallelOne, getChunkCapacity, getChunkOfChunksCapacity, getChunkTimeout, getMaxMemory, getMaxParallel, isAtOnceEvaluation, isBlockedEvaluation, isLastPassRequested, isPipelinedEvaluation, isReorderSolutions, isSharedState, newStats
__replaceArg, _clearProperty, _set, _setProperty, annotations, annotationsCopy, annotationsEqual, annotationsRef, argIterator, args, argsCopy, arity, clearAnnotations, clearProperty, deepCopy, deepCopy, get, getProperty, setArg, setProperty, setUnboundProperty, toArray, toArray
annotationsEqual, annotationsToString, annotationsToString, annotationValueToString, checkArgs, clone, equals, getEvaluationContext, getId, getProperty, getRequiredProperty, hashCode, indent, isController, mutation, shortenName, toShortString, toString, toString
public HTreeDistinctBindingSetsOp(HTreeDistinctBindingSetsOp op)
public HTreeDistinctBindingSetsOp(BOp args, Map<String,Object> annotations)
public FutureTask<Void> eval(BOpContext<IBindingSet> context)
FutureTaskwhich computes the operator against the evaluation context. The caller is responsible for executing the
FutureTask(this gives them the ability to hook the completion of the computation).
context- The evaluation context.
FutureTaskwhich will compute the operator's evaluation.
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