Re: Variable length varlena headers redux

Gregory Stark <stark@enterprisedb.com> writes:
> "Tom Lane" <tgl@sss.pgh.pa.us> writes:
>> Any such site is already broken, because with the proposed design, code
>> is only exposed to short-header datums if it is also exposed to toasted
>> datums.  

> Well the toaster doesn't run until we were about to put the tuple on disk. I
> was afraid there might be circumstances where data from in-memory tuples are
> returned and we use them without fearing them being toasted. In particular I
> was fearing the record/row handling in plpgsql.

True, which is another argument why datatype-specific functions should
never return short-header datums: there are places that call such
functions directly and probably expect an untoasted result.  I'm not
very concerned about stuff that's gone through a tuple though: in most
cases that could be expected to contain toasted values anyway.
        regards, tom lane