Re: Allowed to return possibly TOASTed datums?

On Sat, Dec 14, 2024 at 12:02 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Jan Behrens <jbe-mlist(at)magnetkern(dot)de> writes:
> > Is it allowed to use the following function, assuming the data type is
> > TOASTable?
>
> > PG_FUNCTION_INFO_V1(mytype_pos);
> > Datum mytype_pos(PG_FUNCTION_ARGS) {
> > PG_RETURN_DATUM(GETARG_DATUM(0));
> > }
>
> Absolutely. You can find things equivalent to that in the
> core code, I think.
>

(I'm not a developer, so this is a curiosity question, not a challenge.)

Since the purpose of TOAST is just (I think) to store "large field values"
on disk by dividing into multiple chunks, what would be the purpose of
returning the TOASTed value to Jan's function?

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