Re: The documentation for storage type 'plain' actually allows single byte header

On Sat, Oct 21, 2023 at 09:56:13PM -0400, Bruce Momjian wrote:
> I did some more research.  It turns out that the source slot/planSlot is
> populating its pg_attribute information via makeTargetEntry() and it
> has no concept of a storage type.
> 
> Digging further, I found that we cannot get rid of the the use of
> att->attstorage != TYPSTORAGE_PLAIN in macros ATT_IS_PACKABLE and
> VARLENA_ATT_IS_PACKABLE macros in src/backend/access/common/heaptuple.c
> because there are internal uses of fill_val() that can't handle packed
> varlena headers.
> 
> I ended up with a doc patch that adds a C comment about this odd
> behavior and removes doc text about PLAIN storage not using packed
> headers.

Oops, patch attached.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.