Ron Johnson <ronljohnsonjr(at)gmail(dot)com> writes:
> 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?
Probably not much. There are scenarios where not detoasting
saves work overall, because the object never has to get detoasted;
but I think that's rare. It'd probably look like
UPDATE t SET c = no_op_function(c) WHERE ...
which is something few people would write.
regards, tom lane