On Fri, Dec 15, 2023 at 12:45 PM Sutou Kouhei <k...@clear-code.com> wrote: > > Hi, > > In <caeg8a3jusha6g19nt_ejk15brna6pmecbk7p81izzi71mug...@mail.gmail.com> > "Re: Make COPY format extendable: Extract COPY TO format implementations" > on Fri, 15 Dec 2023 11:27:30 +0800, > Junwang Zhao <zhjw...@gmail.com> wrote: > > >> > Adding a prefix or suffix would be one option but to give extensions > >> > more flexibility, another option would be to support format = 'custom' > >> > and add the "handler" option to specify a copy handler function name > >> > to call. For example, COPY ... FROM ... WITH (FORMAT = 'custom', > >> > HANDLER = 'arrow_copy_handler'). > >> > > I like the prefix/suffix idea, easy to implement. *custom* is not a FORMAT, > > and user has to know the name of the specific handler names, not > > intuitive. > > Ah! I misunderstood this idea. "custom" is the special > format to use "HANDLER". I thought that we can use it like > > (FORMAT = 'arrow', HANDLER = 'arrow_copy_handler_impl1') > > and > > (FORMAT = 'arrow', HANDLER = 'arrow_copy_handler_impl2') > > . > > >> Interesting. If we use this option, users can choose an COPY > >> FORMAT implementation they like from multiple > >> implementations. For example, a developer may implement a > >> COPY FROM FORMAT = 'json' handler with PostgreSQL's JSON > >> related API and another developer may implement a handler > >> with simdjson[1] which is a fast JSON parser. Users can > >> choose whichever they like. > > Not sure about this, why not move Json copy handler to contrib > > as an example for others, any extensions share the same format > > function name and just install one? No bound would implement > > another CSV or TEXT copy handler IMHO. > > I should have used a different format not JSON as an example > for easy to understand. I just wanted to say that extension > developers can implement another implementation without > conflicting another implementation.
Yeah, I can see the value of the HANDLER option now. The possibility of two extensions for the same format using same hanlder name should be rare I guess ;) > > > Thanks, > -- > kou -- Regards Junwang Zhao