Is MaxHeapAttributeNumber a reasonable restriction for foreign-tables?

Hello,

I noticed that CheckAttributeNamesTypes() prevents to create a table that has
more than MaxHeapAttributeNumber (1600) columns, for foreign-table also.
IIUC, this magic number comes from length of the null-bitmap can be covered
with t_hoff in HeapTupleHeaderData.
For heap-tables, it seems to me a reasonable restriction to prevent overrun of
null-bitmap. On the other hand, do we have proper reason to apply same
restrictions on foreign-tables also?

Foreign-tables have their own unique internal data structures instead of
the PostgreSQL's heap-table, and some of foreign-data can have thousands
attributes in their structured data.
I think that MaxHeapAttributeNumber is a senseless restriction for foreign-
tables. How about your opinions?

Best regards,
--
HeteroDB, Inc / The PG-Strom Project
KaiGai Kohei <kaigai(at)heterodb(dot)com>