new

# File activerecord/lib/active_record/insert_all.rb, line 18
    def initialize(relation, connection, inserts, on_duplicate,, update_only: nil, returning: nil, unique_by: nil, record_timestamps: nil)
      @relation = relation
      @model, @connection, @inserts = relation.model, connection, inserts.map(&:stringify_keys)
      @on_duplicate, @update_only, @returning, @unique_by = on_duplicate, update_only, returning, unique_by
      @record_timestamps = record_timestamps.nil? ? model.record_timestamps : record_timestamps

      disallow_raw_sql!(on_duplicate)
      disallow_raw_sql!(returning)

      if @inserts.empty?
        @keys = []
      else
        resolve_sti
        resolve_attribute_aliases
        @keys = @inserts.first.keys
      end

      @scope_attributes = relation.scope_for_create.except(@model.inheritance_column)
      @keys |= @scope_attributes.keys
      @keys = @keys.to_set

      @returning = (connection.supports_insert_returning? ? primary_keys : false) if @returning.nil?
      @returning = false if @returning == []

      @unique_by = find_unique_index_for(@unique_by)

      configure_on_duplicate_update_logic
      ensure_valid_options_for_connection!
    end