This class is used internally by L<DBIx::Class::Storage::DBI::Replicated>. You
shouldn't need to create instances of this class.
-
+
=head1 DESCRIPTION
Given a pool (L<DBIx::Class::Storage::DBI::Replicated::Pool>) of replicated
database's (L<DBIx::Class::Storage::DBI::Replicated::Replicant>), defines a
method by which query load can be spread out across each replicant in the pool.
-This Balancer uses L<List::Util> keyword 'shuffle' to randomly pick an active
-replicant from the associated pool. This may or may not be random enough for
-you, patches welcome.
-
=head1 ATTRIBUTES
This class defines the following attributes.
=head2 master_read_weight
-A number from 0 to 1 that specifies what weight to give the master when choosing
-which backend to execute a read query on. A value of 0, which is the default,
-does no reads from master, while a value of 1 gives it the same priority as any
-single replicant.
+A number greater than 0 that specifies what weight to give the master when
+choosing which backend to execute a read query on. A value of 0, which is the
+default, does no reads from master, while a value of 1 gives it the same
+priority as any single replicant.
+
+For example: if you have 2 replicants, and a L</master_read_weight> of C<0.5>,
+the chance of reading from master will be C<20%>.
+
+You can set it to a value higher than 1, making master have higher weight than
+any single replicant, if for example you have a very powerful master.
=cut
my $self = shift @_;
my @replicants = $self->pool->active_replicants;
+
+ if (not @replicants) {
+ # will fall back to master anyway
+ return;
+ }
+
my $master = $self->master;
- my $rnd = $self->random_number(@replicants + $self->master_read_weight);
+ my $rnd = $self->_random_number(@replicants + $self->master_read_weight);
return $rnd >= @replicants ? $master : $replicants[int $rnd];
}
-=head2 random_number
-
-Returns a random number from 0 to x, not including x. Uses perl's
-L<perlfunc/rand> by default.
-
-=cut
-
-sub random_number {
+sub _random_number {
rand($_[1])
}
-=head1 AUTHOR
+=head1 FURTHER QUESTIONS?
-John Napiorkowski <john.napiorkowski@takkle.com>
+Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>.
-=head1 LICENSE
+=head1 COPYRIGHT AND LICENSE
-You may distribute this code under the same terms as Perl itself.
+This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE>
+by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can
+redistribute it and/or modify it under the same terms as the
+L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>.
=cut