This queue is for tickets about the Set-ConsistentHash CPAN distribution.

Report information
The Basics
Id:
33046
Status:
new
Priority:
Low/Low

People
Owner:
Nobody in particular
Requestors:
takeru.inoue+perl [...] gmail.com
Cc:
AdminCc:

BugTracker
Severity:
Important
Broken in:
0.91
Fixed in:
(no value)

Attachments


Subject: the number of buckets should be configurable
Hi, This patch enables you to change the number of buckets with the new method set_num_buckets(). In order to distribute buckets uniformly among targets (servers), the number of buckets must be greater than 100 * (average weight) * (# targets). The current setting (1024) is too small, when there are several tens of targets. Regards,
Subject: Set-ConsistentHash.pm-num_buckets.patch
--- lib/Set/ConsistentHash.pm-orig 2007-04-27 07:11:43.000000000 +0900 +++ lib/Set/ConsistentHash.pm 2008-02-09 14:17:59.000000000 +0900 @@ -60,6 +60,7 @@ weights => {}, # $target => integer $weight points => {}, # 32-bit value points on 'circle' => \$target order => [], # 32-bit points, sorted + num_buckets => 1024, # the number of buckets buckets => undef, # when requested, arrayref of 1024 buckets mapping to targets total_weight => undef, # when requested, total weight of all targets hash_func => undef, # hash function for key lookup @@ -212,6 +213,22 @@ ############################################################################ +=head2 set_num_buckets + + $set->set_num_buckets($num_buckets); + +Sets the number of buckets, which should be 2^n and greater than +100 * (average weight) * (# targets). + +=cut + +sub set_num_buckets { + my ($self, $num_buckets) = @_; + $self->{num_buckets} = $num_buckets; +} + +############################################################################ + =head2 get_target $selected_target = $set->get_target(your_hash_func($your_key)); @@ -232,7 +249,7 @@ my ($self, $key) = @_; _compute_buckets($self) unless $self->{buckets}; $key = $self->{hash_func}->($key) if $self->{hash_func}; - return $self->{buckets}->[$key % 1024]; + return $self->{buckets}->[$key % $self->{num_buckets}]; } =head2 buckets @@ -273,9 +290,9 @@ sub _compute_buckets { my $self = shift; my @buckets = (); - my $by = 2**22; # 2**32 / 2**10 (1024) + my $by = (2**32 / $self->{num_buckets}); my $pt = 0; - for my $n (0..1023) { + for my $n (0..($self->{num_buckets}-1)) { $buckets[$n] = $self->target_of_point($pt); $pt += $by; }


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