1Attean::QueryPlanner(3)User Contributed Perl DocumentatioAnttean::QueryPlanner(3)
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6 Attean::QueryPlanner - Query planner
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9 This document describes Attean::QueryPlanner version 0.020
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12 use v5.14;
13 use Attean;
14 my $planner = Attean::QueryPlanner->new();
15 my $default_graphs = [ Attean::IRI->new('http://example.org/') ];
16 my $plan = $planner->plan_for_algebra( $algebra, $model, $default_graphs );
17 my $iter = $plan->evaluate($model);
18 while (my $result = $iter->next()) {
19 say $result->as_string;
20 }
21
23 The Attean::QueryPlanner class is a base class implementing common
24 behavior for query planners. Subclasses will need to consume or compose
25 the Attean::API::JoinPlanner role.
26 Trivial sub-classes may consume Attean::API::NaiveJoinPlanner, while
28 more complex planners may choose to implement complex join planning
29 (e.g. Attean::IDPQueryPlanner).
30
33 "new_temporary( $type )"
34 Returns a new unique (in the context of the query planner) ID
35 string that may be used for things like fresh (temporary)
36 variables. The $type string is used in the generated name to aid in
37 identifying different uses for the names.
38 "plan_for_algebra( $algebra, $model, \@active_graphs, \@default_graphs
40 )"
41 Returns the first plan returned from "plans_for_algebra".
42 "plans_for_algebra( $algebra, $model, \@active_graphs, \@default_graphs
44 )"
45 Returns Attean::API::Plan objects representing alternate query
46 plans for evaluating the query $algebra against the $model, using
47 the supplied $active_graph.
48 "simplify_path( $subject, $path, $object )"
50 Return a simplified Attean::API::Algebra object corresponding to
51 the given property path.
52 "new_projection( $plan, $distinct, @variable_names )"
54 Return a new Attean::Plan::Project plan over $plan, projecting the
55 named variables. $disctinct should be true if the caller can
56 guarantee that the resulting plan will produce distinct results,
57 false otherwise.
58 This method takes care of computing plan metadata such as the
60 resulting ordering.
61 "bgp_join_plans( $bgp, $model, \@active_graphs, \@default_graphs,
63 \@interesting_order, \@plansA, \@plansB, ... )"
64 Returns a list of alternative plans for the join of a set of
65 triples. The arguments @plansA, @plansB, etc. represent
66 alternative plans for each triple participating in the join.
67 "group_join_plans( $model, \@active_graphs, \@default_graphs,
69 \@interesting_order, \@plansA, \@plansB, ... )"
70 Returns a list of alternative plans for the join of a set of sub-
71 plans. The arguments @plansA, @plansB, etc. represent alternative
72 plans for each sub-plan participating in the join.
73 "joins_for_plan_alternatives( $model, \@active_graphs,
75 \@default_graphs, $interesting, \@plan_A, \@plan_B, ... )"
76 Returns a list of alternative plans that may all be used to produce
77 results matching the join of "plan_A", " plan_B ">, etc. Each plan
78 array here (e.g. @plan_A) should contain equivalent plans.
79 "access_plans( $model, $active_graphs, $pattern )"
81 Returns a list of alternative Attean::API::Plan objects that may be
82 used to produce results matching the
83 Attean::API::TripleOrQuadPattern $pattern in the context of
84 $active_graphs.
85 "join_plans( $model, \@active_graphs, \@default_graphs, \@plan_left,
87 \@plan_right, $type [, $expr] )"
88 Returns a list of alternative plans for the join of one plan from
89 @plan_left and one plan from @plan_right. The join $type must be
90 one of 'inner', 'left', or 'minus', indicating the join algorithm
91 to be used. If $type is 'left', then the optional $expr may be used
92 to supply a filter expression that should be used by the SPARQL
93 left-join algorithm.
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96 Please report any bugs or feature requests to through the GitHub web
97 interface at <https://github.com/kasei/attean/issues>.
98
101 Gregory Todd Williams "<gwilliams@cpan.org>"
102
104 Copyright (c) 2014--2018 Gregory Todd Williams. This program is free
105 software; you can redistribute it and/or modify it under the same terms
106 as Perl itself.
107perl v5.28.1 2019-01-09 Attean::QueryPlanner(3)