Sha256: 8f9af24cb2f5da71d396fb2c6ef9848fabab6e9df7f4fc0ecf096f03dda0737e
Contents?: true
Size: 1.28 KB
Versions: 23
Compression:
Stored size: 1.28 KB
Contents
# -*- coding: utf-8 -*-
require 'bsearch'
module ActiveRecord::Turntable::Algorithm
class RangeBsearchAlgorithm < Base
def initialize(config)
@config = config
@config["shards"].sort_by! {|a| a["less_than"]}
end
def calculate(key)
idx = calculate_idx(key)
@config["shards"][idx]["connection"]
rescue
raise ActiveRecord::Turntable::CannotSpecifyShardError, "cannot specify shard for key:#{key}"
end
def calculate_idx(key)
@config["shards"].bsearch_upper_boundary { |h|
h["less_than"] <=> key
}
end
# { connection_name => weight, ... }
def calculate_used_shards_with_weight(sequence_value)
idx = calculate_idx(sequence_value)
last_connection = calculate(sequence_value)
shards = @config["shards"][0..idx]
weighted_hash = Hash.new {|h,k| h[k]=0}
prev_max = 0
shards.each_with_index do |h,idx|
weighted_hash[h["connection"]] += if idx < shards.size - 1
h["less_than"] - prev_max - 1
else
sequence_value - prev_max
end
prev_max = h["less_than"] - 1
end
return weighted_hash
end
end
end
Version data entries
23 entries across 23 versions & 1 rubygems