Class: ActiveRecord::Turntable::Algorithm::RangeBsearchAlgorithm
- Defined in:
- lib/active_record/turntable/algorithm/range_bsearch_algorithm.rb
Instance Method Summary collapse
- #calculate(key) ⇒ Object
- #calculate_idx(key) ⇒ Object
-
#calculate_used_shards_with_weight(sequence_value) ⇒ Object
{ connection_name => weight, … }.
-
#initialize(config) ⇒ RangeBsearchAlgorithm
constructor
A new instance of RangeBsearchAlgorithm.
Constructor Details
#initialize(config) ⇒ RangeBsearchAlgorithm
Returns a new instance of RangeBsearchAlgorithm.
5 6 7 8 |
# File 'lib/active_record/turntable/algorithm/range_bsearch_algorithm.rb', line 5 def initialize(config) @config = config @config[:shards].sort_by! { |a| a[:less_than] } end |
Instance Method Details
#calculate(key) ⇒ Object
10 11 12 13 14 15 |
# File 'lib/active_record/turntable/algorithm/range_bsearch_algorithm.rb', line 10 def calculate(key) idx = calculate_idx(key) @config[:shards][idx][:connection] rescue raise ActiveRecord::Turntable::CannotSpecifyShardError, "cannot specify shard for key:#{key}" end |
#calculate_idx(key) ⇒ Object
17 18 19 20 21 |
# File 'lib/active_record/turntable/algorithm/range_bsearch_algorithm.rb', line 17 def calculate_idx(key) @config[:shards].bsearch_upper_boundary { |h| h[:less_than] <=> key } end |
#calculate_used_shards_with_weight(sequence_value) ⇒ Object
{ connection_name => weight, … }
24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 |
# File 'lib/active_record/turntable/algorithm/range_bsearch_algorithm.rb', line 24 def calculate_used_shards_with_weight(sequence_value) current_shard_idx = calculate_idx(sequence_value) shards = @config[:shards][0..current_shard_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 weighted_hash end |