Module: Switchman::ActiveRecord::Calculations
- Defined in:
- lib/switchman/active_record/calculations.rb
Class Method Summary collapse
Instance Method Summary collapse
- #calculate_simple_average(column_name, distinct) ⇒ Object
-
#execute_grouped_calculation(operation, column_name, distinct) ⇒ Object
See activerecord#execute_grouped_calculation.
- #execute_simple_calculation_with_sharding(operation, column_name, distinct) ⇒ Object
- #pluck_with_sharding(column_name) ⇒ Object
Class Method Details
.included(klass) ⇒ Object
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# File 'lib/switchman/active_record/calculations.rb', line 4 def self.included(klass) %w{execute_simple_calculation pluck}.each do |method| klass.alias_method_chain(method, :sharding) end end |
Instance Method Details
#calculate_simple_average(column_name, distinct) ⇒ Object
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# File 'lib/switchman/active_record/calculations.rb', line 47 def calculate_simple_average(column_name, distinct) # See activerecord#execute_simple_calculation relation = reorder(nil) column = aggregate_column(column_name) relation.select_values = [operation_over_aggregate_column(column, "average", distinct).as("average"), operation_over_aggregate_column(column, "count", distinct).as("count")] initial_results = relation.activate{ |rel| klass.connection.select_all(rel) } if initial_results.is_a?(Array) initial_results.each do |r| r["average"] = type_cast_calculated_value(r["average"], column_for(column_name), "average") r["count"] = type_cast_calculated_value(r["count"], column_for(column_name), "count") end result = initial_results.map{|r| r["average"] * r["count"]}.sum / initial_results.map{|r| r["count"]}.sum else result = type_cast_calculated_value(initial_results.first["average"], column_for(column_name), "average") end result end |
#execute_grouped_calculation(operation, column_name, distinct) ⇒ Object
See activerecord#execute_grouped_calculation
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# File 'lib/switchman/active_record/calculations.rb', line 68 def execute_grouped_calculation(operation, column_name, distinct) opts = (operation.to_s.downcase, column_name, distinct) relation = build_grouped_calculation_relation(opts) target_shard = Shard.current(:default) rows = relation.activate do |rel, shard| calculated_data = klass.connection.select_all(rel) if opts[:association] key_ids = calculated_data.collect { |row| row[opts[:group_aliases].first] } key_records = opts[:association].klass.base_class.where(:id => key_ids) key_records = Hash[key_records.map { |r| [Shard.relative_id_for(r, shard, target_shard), r] }] end calculated_data.map do |row| row[opts[:aggregate_alias]] = type_cast_calculated_value( row[opts[:aggregate_alias]], column_for(opts[:column_name]), opts[:operation]) row['count'] = row['count'].to_i if opts[:operation] == 'average' opts[:group_columns].each do |aliaz, column| if opts[:associated] && (aliaz == opts[:group_aliases].first) row[aliaz] = key_records[Shard.relative_id_for(row[aliaz], shard, target_shard)] elsif column && @klass.sharded_column?(column.name) row[aliaz] = Shard.relative_id_for(type_cast_calculated_value(row[aliaz], column), shard, target_shard) end end row end end compact_grouped_calculation_rows(rows, opts) end |
#execute_simple_calculation_with_sharding(operation, column_name, distinct) ⇒ Object
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# File 'lib/switchman/active_record/calculations.rb', line 27 def execute_simple_calculation_with_sharding(operation, column_name, distinct) operation = operation.to_s.downcase if operation == "average" result = calculate_simple_average(column_name, distinct) else result = self.activate{ |relation| relation.send(:execute_simple_calculation_without_sharding, operation, column_name, distinct) } if result.is_a?(Array) case operation when "count", "sum" result = result.sum when "minimum" result = result.min when "maximum" result = result.max end end end result end |
#pluck_with_sharding(column_name) ⇒ Object
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# File 'lib/switchman/active_record/calculations.rb', line 10 def pluck_with_sharding(column_name) target_shard = Shard.current(klass.shard_category) shard_count = 0 result = self.activate do |relation, shard| shard_count += 1 results = relation.pluck_without_sharding(column_name) if klass.sharded_column?(column_name.to_s) results = results.map{|result| Shard.relative_id_for(result, shard, target_shard)} end results end if uniq_value && shard_count > 1 result.uniq! end result end |