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.IX Title "Attean::QueryPlanner 3pm"
.TH Attean::QueryPlanner 3pm "2022-10-06" "perl v5.34.0" "User Contributed Perl Documentation"
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.SH "NAME"
Attean::QueryPlanner \- Query planner
.SH "VERSION"
.IX Header "VERSION"
This document describes Attean::QueryPlanner version 0.033
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 9
\&  use v5.14;
\&  use Attean;
\&  my $planner = Attean::QueryPlanner\->new();
\&  my $default_graphs = [ Attean::IRI\->new(\*(Aqhttp://example.org/\*(Aq) ];
\&  my $plan = $planner\->plan_for_algebra( $algebra, $model, $default_graphs );
\&  my $iter = $plan\->evaluate($model);
\&  while (my $result = $iter\->next()) {
\&    say $result\->as_string;
\&  }
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The Attean::QueryPlanner class is a base class implementing common behavior for
query planners. Subclasses will need to consume or compose the
Attean::API::JoinPlanner role.
.PP
Trivial sub-classes may consume Attean::API::NaiveJoinPlanner, while more
complex planners may choose to implement complex join planning (e.g.
Attean::IDPQueryPlanner).
.SH "ATTRIBUTES"
.IX Header "ATTRIBUTES"
.SH "METHODS"
.IX Header "METHODS"
.ie n .IP """new_temporary( $type )""" 4
.el .IP "\f(CWnew_temporary( $type )\fR" 4
.IX Item "new_temporary( $type )"
Returns a new unique (in the context of the query planner) \s-1ID\s0 string that may
be used for things like fresh (temporary) variables. The \f(CW$type\fR string is
used in the generated name to aid in identifying different uses for the names.
.ie n .IP """plan_for_algebra( $algebra, $model, \e@active_graphs, \e@default_graphs )""" 4
.el .IP "\f(CWplan_for_algebra( $algebra, $model, \e@active_graphs, \e@default_graphs )\fR" 4
.IX Item "plan_for_algebra( $algebra, $model, @active_graphs, @default_graphs )"
Returns the first plan returned from \f(CW\*(C`plans_for_algebra\*(C'\fR.
.ie n .IP """plans_for_algebra( $algebra, $model, \e@active_graphs, \e@default_graphs )""" 4
.el .IP "\f(CWplans_for_algebra( $algebra, $model, \e@active_graphs, \e@default_graphs )\fR" 4
.IX Item "plans_for_algebra( $algebra, $model, @active_graphs, @default_graphs )"
Returns Attean::API::Plan objects representing alternate query plans for
evaluating the query \f(CW$algebra\fR against the \f(CW$model\fR, using
the supplied \f(CW$active_graph\fR.
.ie n .IP """simplify_path( $subject, $path, $object )""" 4
.el .IP "\f(CWsimplify_path( $subject, $path, $object )\fR" 4
.IX Item "simplify_path( $subject, $path, $object )"
Return a simplified Attean::API::Algebra object corresponding to the given
property path.
.ie n .IP """new_projection( $plan, $distinct, @variable_names )""" 4
.el .IP "\f(CWnew_projection( $plan, $distinct, @variable_names )\fR" 4
.IX Item "new_projection( $plan, $distinct, @variable_names )"
Return a new Attean::Plan::Project plan over \f(CW$plan\fR, projecting
the named variables. \f(CW$disctinct\fR should be true if the caller can
guarantee that the resulting plan will produce distinct results, false otherwise.
.Sp
This method takes care of computing plan metadata such as the resulting ordering.
.ie n .IP """bgp_join_plans( $bgp, $model, \e@active_graphs, \e@default_graphs, \e@interesting_order, \e@plansA, \e@plansB, ... )""" 4
.el .IP "\f(CWbgp_join_plans( $bgp, $model, \e@active_graphs, \e@default_graphs, \e@interesting_order, \e@plansA, \e@plansB, ... )\fR" 4
.IX Item "bgp_join_plans( $bgp, $model, @active_graphs, @default_graphs, @interesting_order, @plansA, @plansB, ... )"
Returns a list of alternative plans for the join of a set of triples.
The arguments \f(CW@plansA\fR, \f(CW@plansB\fR, etc. represent alternative plans for each
triple participating in the join.
.ie n .IP """group_join_plans( $model, \e@active_graphs, \e@default_graphs, \e@interesting_order, \e@plansA, \e@plansB, ... )""" 4
.el .IP "\f(CWgroup_join_plans( $model, \e@active_graphs, \e@default_graphs, \e@interesting_order, \e@plansA, \e@plansB, ... )\fR" 4
.IX Item "group_join_plans( $model, @active_graphs, @default_graphs, @interesting_order, @plansA, @plansB, ... )"
Returns a list of alternative plans for the join of a set of sub-plans.
The arguments \f(CW@plansA\fR, \f(CW@plansB\fR, etc. represent alternative plans for each
sub-plan participating in the join.
.ie n .IP """joins_for_plan_alternatives( $model, \e@active_graphs, \e@default_graphs, $interesting, \e@plan_A, \e@plan_B, ... )""" 4
.el .IP "\f(CWjoins_for_plan_alternatives( $model, \e@active_graphs, \e@default_graphs, $interesting, \e@plan_A, \e@plan_B, ... )\fR" 4
.IX Item "joins_for_plan_alternatives( $model, @active_graphs, @default_graphs, $interesting, @plan_A, @plan_B, ... )"
Returns a list of alternative plans that may all be used to produce results
matching the join of \f(CW\*(C`plan_A\*(C'\fR, \f(CW\*(C` plan_B \*(C'\fR>, etc. Each plan array here
(e.g. \f(CW@plan_A\fR) should contain equivalent plans.
.ie n .IP """access_plans( $model, $active_graphs, $pattern )""" 4
.el .IP "\f(CWaccess_plans( $model, $active_graphs, $pattern )\fR" 4
.IX Item "access_plans( $model, $active_graphs, $pattern )"
Returns a list of alternative Attean::API::Plan objects that may be used to
produce results matching the Attean::API::TripleOrQuadPattern \f(CW$pattern\fR in
the context of \f(CW$active_graphs\fR.
.ie n .IP """join_plans( $model, \e@active_graphs, \e@default_graphs, \e@plan_left, \e@plan_right, $type [, $expr] )""" 4
.el .IP "\f(CWjoin_plans( $model, \e@active_graphs, \e@default_graphs, \e@plan_left, \e@plan_right, $type [, $expr] )\fR" 4
.IX Item "join_plans( $model, @active_graphs, @default_graphs, @plan_left, @plan_right, $type [, $expr] )"
Returns a list of alternative plans for the join of one plan from \f(CW@plan_left\fR
and one plan from \f(CW@plan_right\fR. The join \f(CW$type\fR must be one of
\&\f(CW\*(Aqinner\*(Aq\fR, \f(CW\*(Aqleft\*(Aq\fR, or \f(CW\*(Aqminus\*(Aq\fR, indicating the join algorithm
to be used. If \f(CW$type\fR is \f(CW\*(Aqleft\*(Aq\fR, then the optional \f(CW$expr\fR
may be used to supply a filter expression that should be used by the \s-1SPARQL\s0
left-join algorithm.
.SH "BUGS"
.IX Header "BUGS"
Please report any bugs or feature requests to through the GitHub web interface
at <https://github.com/kasei/attean/issues>.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
.SH "AUTHOR"
.IX Header "AUTHOR"
Gregory Todd Williams  \f(CW\*(C`<gwilliams@cpan.org>\*(C'\fR
.SH "COPYRIGHT"
.IX Header "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.