Re: Packed short varlenas, what next?

I wrote:
> Gregory Stark <stark@enterprisedb.com> writes:
>> I'm really curious to know how people feel about the varlena patch.

> One thing I think we could do immediately is apply the change to replace
> "VARATT_SIZEP(x) = len" with "SET_VARSIZE(x, len)" --- that would
> considerably reduce the size of the patch and allow people to focus on
> the important changes instead of underbrush.  Barring objection I'll go
> ahead and do that today.

I've committed this, but in testing with a hack that does ntohl() in the
VARSIZE macro and vice-versa in SET_VARSIZE, I find that core passes
regression but several contrib modules do not.  It looks like the
contrib modules were depending on various random structs being
compatible with varlena, while not exposing that dependence in ways that
either of us caught :-(.

I'll work on cleaning up the remaining mess tomorrow, but I think that
we may need to think twice about whether it's OK to expect that every
datatype with typlen = -1 will be compatible with the New Rules.  I'm
back to wondering if maybe only types with typalign 'c' should get
caught up in the changes.
        regards, tom lane