| … | |
… | |
| 855 | This also saves round-trips and avoids sending messages to the wrong port |
855 | This also saves round-trips and avoids sending messages to the wrong port |
| 856 | (hard to do in Erlang). |
856 | (hard to do in Erlang). |
| 857 | |
857 | |
| 858 | =back |
858 | =back |
| 859 | |
859 | |
|
|
860 | =head1 RATIONALE |
|
|
861 | |
|
|
862 | =over 4 |
|
|
863 | |
|
|
864 | =item Why strings for ports and noderefs, why not objects? |
|
|
865 | |
|
|
866 | We considered "objects", but found that the actual number of methods |
|
|
867 | thatc an be called are very low. Since port IDs and noderefs travel over |
|
|
868 | the network frequently, the serialising/deserialising would add lots of |
|
|
869 | overhead, as well as having to keep a proxy object. |
|
|
870 | |
|
|
871 | Strings can easily be printed, easily serialised etc. and need no special |
|
|
872 | procedures to be "valid". |
|
|
873 | |
|
|
874 | And a a miniport consists of a single closure stored in a global hash - it |
|
|
875 | can't become much cheaper. |
|
|
876 | |
|
|
877 | =item Why favour JSON, why not real serialising format such as Storable? |
|
|
878 | |
|
|
879 | In fact, any AnyEvent::MP node will happily accept Storable as framing |
|
|
880 | format, but currently there is no way to make a node use Storable by |
|
|
881 | default. |
|
|
882 | |
|
|
883 | The default framing protocol is JSON because a) JSON::XS is many times |
|
|
884 | faster for small messages and b) most importantly, after years of |
|
|
885 | experience we found that object serialisation is causing more problems |
|
|
886 | than it gains: Just like function calls, objects simply do not travel |
|
|
887 | easily over the network, mostly because they will always be a copy, so you |
|
|
888 | always have to re-think your design. |
|
|
889 | |
|
|
890 | Keeping your messages simple, concentrating on data structures rather than |
|
|
891 | objects, will keep your messages clean, tidy and efficient. |
|
|
892 | |
|
|
893 | =back |
|
|
894 | |
| 860 | =head1 SEE ALSO |
895 | =head1 SEE ALSO |
| 861 | |
896 | |
| 862 | L<AnyEvent>. |
897 | L<AnyEvent>. |
| 863 | |
898 | |
| 864 | =head1 AUTHOR |
899 | =head1 AUTHOR |
