minor replication changes - use a real hash merge, clarify master_read_weight, really...

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / Storage / DBI / Replicated / Balancer / Random.pm

diff --git a/lib/DBIx/Class/Storage/DBI/Replicated/Balancer/Random.pm b/lib/DBIx/Class/Storage/DBI/Replicated/Balancer/Random.pm
index 2b0aef9..f23db75 100644 (file)
--- a/lib/DBIx/Class/Storage/DBI/Replicated/Balancer/Random.pm
+++ b/lib/DBIx/Class/Storage/DBI/Replicated/Balancer/Random.pm
@@ -30,10 +30,16 @@ 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
 
@@ -55,21 +61,20 @@ sub next_storage {
   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])
 }