On Mon, Dec 11, 2023 at 7:19 PM Michael Paquier <mich...@paquier.xyz> wrote: > > On Mon, Dec 11, 2023 at 10:57:15AM +0900, Masahiko Sawada wrote: > > IIUC we cannot create two same name functions with the same arguments > > but a different return value type in the first place. It seems to me > > to be an overkill to change such a design. > > Agreed to not touch the logictics of LookupFuncName() for the sake of > this thread. I have not checked the SQL specification, but I recall > that there are a few assumptions from the spec embedded in the lookup > logic particularly when it comes to specify a procedure name without > arguments. > > > Another idea is to encapsulate copy_to/from_handler by a super class > > like copy_handler. The handler function is called with an argument, > > say copyto, and returns copy_handler encapsulating either > > copy_to/from_handler depending on the argument. > > Yep, that's possible as well and can work as a cross-check between the > argument and the NodeTag assigned to the handler structure returned by > the function. > > At the end, the final result of the patch should IMO include: > - Documentation about how one can register a custom copy_handler. > - Something in src/test/modules/, minimalistic still useful that can > be used as a template when one wants to implement their own handler. > The documentation should mention about this module. > - No need for SQL functions for all the in-core handlers: let's just > return pointers to them based on the options given.
Agreed. > It would be probably cleaner to split the patch so as the code is > refactored and evaluated with the in-core handlers first, and then > extended with the pluggable facilities and the function lookups. Agreed. I've sketched the above idea including a test module in src/test/module/test_copy_format, based on v2 patch. It's not splitted and is dirty so just for discussion. Regards, -- Masahiko Sawada Amazon Web Services: https://aws.amazon.com
custom_copy_format_draft.patch
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