/usr/share/perl5/AtteanX/API/JoinRotatingPlanner.pm is in libattean-perl 0.017-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 | use v5.14;
use warnings;
=encoding utf8
=head1 NAME
AtteanX::API::JoinRotatingPlanner - Query planning role to produce alternative join plans
=head1 VERSION
This document describes AtteanX::API::JoinRotatingPlanner version 0.017
=head1 DESCRIPTION
The AtteanX::API::JoinRotatingPlanner role, when used with L<Attean::QueryPlanner>,
produces alternatives for join query plans. Specifically, joins of the form
(A⋈B)⋈C are rotated to A⋈(B⋈C), with the ability to coalesce B⋈C (e.g. for
adjacent BGPs).
=head1 REQUIRED METHODS
=over 4
=item C<< allow_join_rotation( $join_plan ) >>
Returns true if join rotation should be attempted on the given join plan.
=item C<< coalesce_rotated_join( $join_plan ) >>
Given a L<Attean::API::Plan::Join> plan C<< $join_plan >>, returns a list of
equivalent plans. This is useful when the join can be reduced to a more
fundamental plan type, such as merging two adjacent BGP plans into a single
plan.
=cut
package AtteanX::API::JoinRotatingPlanner 0.017 {
# Rotate joins like (A⋈B)⋈C to A⋈(B⋈C), with the ability to coalesce B⋈C (e.g. for adjacent BGPs)
use Moo::Role;
use Attean;
use Attean::RDF;
use namespace::clean;
requires 'coalesce_rotated_join';
requires 'allow_join_rotation';
sub allow_join_rotation {
return 1;
}
sub coalesce_rotated_join {
my $self = shift;
my $plan = shift;
return $plan;
}
around 'join_plans' => sub {
my $orig = shift;
my $self = shift;
my $model = shift;
my $active_graphs = shift;
my $default_graphs = shift;
my $lplans = shift;
my $rplans = shift;
my $type = shift;
my @plans = $orig->($self, $model, $active_graphs, $default_graphs, $lplans, $rplans, $type, @_);
if ($type eq 'inner') {
my @rotated;
foreach my $p (@plans) {
if ($self->allow_join_rotation($p)) {
my ($lhs, $rhs) = @{ $p->children };
if ($lhs->does('Attean::API::Plan::Join')) {
my ($a, $b) = @{ $lhs->children };
my $c = $rhs;
# (A⋈B)⋈C -> A⋈(B⋈C)
foreach my $q ($orig->($self, $model, $active_graphs, $default_graphs, [$b], [$c], $type, @_)) {
push(@rotated, $orig->($self, $model, $active_graphs, $default_graphs, [$a], [$self->coalesce_rotated_join($q)], $type, @_))
}
} elsif ($rhs->does('Attean::API::Plan::Join')) {
my $a = $lhs;
my ($b, $c) = @{ $rhs->children };
# A⋈(B⋈C) -> (A⋈B)⋈C
foreach my $q ($orig->($self, $model, $active_graphs, $default_graphs, [$a], [$b], $type, @_)) {
push(@rotated, $orig->($self, $model, $active_graphs, $default_graphs, [$self->coalesce_rotated_join($q)], [$c], $type, @_));
}
}
}
push(@rotated, $p);
}
return @rotated;
} else {
return @plans;
}
};
}
1;
__END__
=back
=head1 BUGS
Please report any bugs or feature requests to through the GitHub web interface
at L<https://github.com/kasei/attean/issues>.
=head1 SEE ALSO
L<http://www.perlrdf.org/>
=head1 AUTHOR
Gregory Todd Williams C<< <gwilliams@cpan.org> >>
=head1 COPYRIGHT
Copyright (c) 2014--2016 Gregory Todd Williams.
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
=cut
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