st 18. 9. 2024 v 16:25 odesílatel Florents Tselai <florents.tse...@gmail.com> napsal:
> > > On Wed, Sep 18, 2024 at 1:09 PM Pavel Stehule <pavel.steh...@gmail.com> > wrote: > >> Hi >> >> st 18. 9. 2024 v 9:04 odesílatel Florents Tselai < >> florents.tse...@gmail.com> napsal: >> >>> Correct me if I'm wrong, >>> but for an extension that defines composite types, >>> there's currently no easy way to get a TupleDesc, even for its own types. >>> >>> Something like >>> TupleDesc get_extension_type_tupledesc(const char *extname, const char >>> *typname) >>> >>> Here's a routine I've stolen borrowed from pramsey's code and have been >>> using ever since. >>> >>> Could this be exposed in extension.h ? (probably without the version >>> check) >>> >> >> I don't think this functionality is generally useful. Wrapping >> TypeGetTupleDesc(typoid, NIL) is very specific, and probably this code >> should be inside the extension. >> >> Different question is API for searching in system catalog and >> dependencies. I can imagine some functions like >> > > That's a better phrasing > >> >> Oid extid = get_extension_id(extname); >> Oid objid = get_extension_object_id(extid, schema_can_be_null, name, >> TYPEOID); // can be used for routine, table, ... >> >> tupdesc = TypeGetTupleDesc(objid, NIL); >> > > These are valid. > For context: > The "problem" (inconvenience really) I'm trying to solve is this: > Most extensions define some convenient PG_GETARG_MYTYPE(n) macros. > When these types are varlena, things are easy. > > When they're composite types though things get more verbose. > i.e. the lines of code the author needs to get from a Datum argument to > struct MyType are too many > and multiple extensions copy-paste the same logic. > > My hope is we could come up with a few routines that ease and standardize > this a bit. > > You're right that extname isn't unique, so Oid should be the argument for > extension, rather than char *extname, > but in my mind the "default" is "the current extension" , but no arguing > about that. > what you mean "the current extension" - there is nothing like this. The functions have not any information without searching in the catalog about their extension. Function knows just its own oid and arguments. I can imagine so fmgr can be enhanced by it - it can reduce some searching, but currently there is nothing like current or owner extension (extension id). >> Regards >> >> Pavel >> >> >>
