NAME¶

Attean::Plan - Representation of SPARQL query plan operators

VERSION¶

This document describes Attean::Plan version 0.034

SYNOPSIS¶

  use v5.14;
  use Attean;

DESCRIPTION¶

This is a utility package that defines all the Attean query plan classes in the Attean::Plan namespace:

• Attean::Plan::Quad

  Evaluates a quad pattern against the model.

• Attean::Plan::NestedLoopJoin

  Evaluates a join (natural-, anti-, or left-) using a nested loop.

• Attean::Plan::HashJoin

  Evaluates a join (natural-, anti-, or left-) using a hash join.

• Attean::Plan::Construct
• Attean::Plan::Describe
• Attean::Plan::EBVFilter

  Filters results from a sub-plan based on the effective boolean value of a named variable binding.

• Attean::Plan::Merge

  Evaluates a set of sub-plans, returning the merged union of results, preserving ordering.

• Attean::Plan::Union

  Evaluates a set of sub-plans, returning the union of results.

• Attean::Plan::Extend

  Evaluates a sub-plan, and extends each result by evaluating a set of expressions, binding the produced values to new variables.

• Attean::Plan::HashDistinct

  Evaluates a sub-plan, and returns distinct results by checking a persistent hash of already-seen results.

• Attean::Plan::Unique

  Evaluates an already-ordered sub-plan, and returns distinct results by filtering out sequential duplicates.

• Attean::Plan::Slice

  Evaluates a sub-plan, and returns the results after optionally skipping some number of results ("offset") and limiting the total number of returned results ("limit").

• Attean::Plan::Project

  Evaluates a sub-plan and returns projected results by only keeping a fixed-set of variable bindings in each result.

• Attean::Plan::OrderBy

  Evaluates a sub-plan and returns the results after fully materializing and sorting is applied.

• Attean::Plan::Service

  Evaluates a SPARQL query against a remote endpoint.

• Attean::Plan::Table

  Returns a constant set of results.

• Attean::Plan::Iterator

  Returns a constant set of results.

  Be aware that if the iterator being wrapped is not repeatable (consuming the Attean::API::RepeatableIterator role), then this plan may only be evaluated once.

  A size estimate may be given if it is available. If the iterator is an Attean::ListIterator, the size of that iterator will be used.

• Attean::Plan::ALPPath
• Attean::Plan::Exists

  Returns an iterator containing a single boolean term indicating whether any results were produced by evaluating the sub-plan.

• Attean::Plan::Aggregate
• Attean::Plan::Unfold

BUGS¶

Please report any bugs or feature requests to through the GitHub web interface at <https://github.com/kasei/attean/issues>.

SEE ALSO¶

AUTHOR¶

Gregory Todd Williams "<gwilliams@cpan.org>"

COPYRIGHT¶

Copyright (c) 2014--2022 Gregory Todd Williams. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.