Module: Switchman::ActiveRecord::Calculations

Defined in:
lib/switchman/active_record/calculations.rb

Instance Method Summary collapse

Instance Method Details

#calculate_simple_average(column_name, distinct) ⇒ Object 



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# File 'lib/switchman/active_record/calculations.rb', line 51

def calculate_simple_average(column_name, distinct)
  # See activerecord#execute_simple_calculation
  relation = except(:order)
  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_switchman(r["average"], column_name, "average")
      r["count"] = type_cast_calculated_value_switchman(r["count"], column_name, "count")
    end
    result = initial_results.sum { |r| r["average"] * r["count"] } / initial_results.sum do |r|
                                                                       r["count"]
                                                                     end
  else
    result = type_cast_calculated_value_switchman(initial_results.first["average"], 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 74

def execute_grouped_calculation(operation, column_name, distinct)
  opts = grouped_calculation_options(operation.to_s.downcase, column_name, distinct)

  relation = build_grouped_calculation_relation(opts)
  target_shard = Shard.current

  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 = key_records.to_h { |r| [Shard.relative_id_for(r, shard, target_shard), r] }
    end

    calculated_data.map do |row|
      row[opts[:aggregate_alias]] = type_cast_calculated_value_switchman(
        row[opts[:aggregate_alias]], column_name, opts[:operation]
      )
      row["count"] = row["count"].to_i if opts[:operation] == "average"

      opts[:group_columns].each do |aliaz, _type, group_column_name|
        if opts[:associated] && (aliaz == opts[:group_aliases].first)
          row[aliaz] = key_records[Shard.relative_id_for(row[aliaz], shard, target_shard)]
        elsif group_column_name && @klass.sharded_column?(group_column_name)
          row[aliaz] = Shard.relative_id_for(row[aliaz], shard, target_shard)
        end
      end
      row
    end
  end

  compact_grouped_calculation_rows(rows, opts)
end

#execute_simple_calculation(operation, column_name, distinct) ⇒ Object 



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# File 'lib/switchman/active_record/calculations.rb', line 29

def execute_simple_calculation(operation, column_name, distinct)
  operation = operation.to_s.downcase
  if operation == "average"
    result = calculate_simple_average(column_name, distinct)
  else
    result = activate do |relation|
      relation.call_super(:execute_simple_calculation, Calculations, operation, column_name, distinct)
    end
    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

#ids ⇒ Object 



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# File 'lib/switchman/active_record/calculations.rb', line 110

def ids
  return super unless klass.sharded_primary_key?

  if loaded?
    result = records.map do |record|
      Shard.relative_id_for(record._read_attribute(primary_key),
                            record.shard,
                            Shard.current(klass.connection_class_for_self))
    end
    return @async ? Promise::Complete.new(result) : result
  end

  if has_include?(primary_key)
    relation = apply_join_dependency.group(primary_key)
    return relation.ids
  end

  columns = arel_columns([primary_key])
  base_shard = Shard.current(klass.connection_class_for_self)
  activate do |r|
    relation = r.spawn
    relation.select_values = columns

    result = if relation.where_clause.contradiction?
               ::ActiveRecord::Result.empty
             else
               skip_query_cache_if_necessary do
                 klass.connection.select_all(relation, "#{klass.name} Ids", async: @async)
               end
             end

    result.then do |res|
      type_cast_pluck_values(res, columns).map { |id| Shard.relative_id_for(id, Shard.current, base_shard) }
    end
  end
end

#pluck(*column_names) ⇒ Object 



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# File 'lib/switchman/active_record/calculations.rb', line 6

def pluck(*column_names)
  target_shard = Shard.current(klass.connection_class_for_self)
  shard_count = 0
  result = activate do |relation, shard|
    shard_count += 1
    results = relation.call_super(:pluck, Calculations, *column_names)
    if column_names.length > 1
      column_names.each_with_index do |column_name, idx|
        next unless klass.sharded_column?(column_name)

        results.each do |r|
          r[idx] = Shard.relative_id_for(r[idx], shard, target_shard)
        end
      end
    elsif klass.sharded_column?(column_names.first.to_s)
      results = results.map { |r| Shard.relative_id_for(r, shard, target_shard) }
    end
    results
  end
  result.uniq! if distinct_value && shard_count > 1
  result
end