Re: Variable length varlena headers redux

Greg Stark <gsstark@mit.edu> writes:
> Bruce Momjian <bruce@momjian.us> writes:
>> I know it is kind of odd to have a data type that is only used on disk,
>> and not in memory, but I see this as a baby varlena type, used only to
>> store and get varlena values using less disk space.

> I was leaning toward generating the short varlena headers primarily in
> heap_form*tuple and just having the datatype specific code generate 4-byte
> headers much as you describe.

I thought we had a solution for all this, namely to make the short-form
headers be essentially a TOAST-compressed representation.  The format
with 4-byte headers is still legal but just not compressed.  Anyone who
fails to detoast an input argument is already broken, so there's no code
compatibility hit taken.
        regards, tom lane