explain

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 179
      def explain(arel, binds = [])
        sql     = "EXPLAIN #{to_sql(arel, binds)}"
        start   = Concurrent.monotonic_time
        result  = exec_query(sql, "EXPLAIN", binds)
        elapsed = Concurrent.monotonic_time - start

        MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
      end