Hi,
FORCE_NOT_NULL and FORCE_NULL are only used when COPY FROM.
And copyto.c and copyfrom.c are split in this commit https://github.com/postgres/postgres//commit/c532d15dddff14b01fe9ef1d465013cb8ef186df <https://github.com/postgres/postgres//commit/c532d15dddff14b01fe9ef1d465013cb8ef186df> .
There is no need to handle these options when COPY TO.
Regards,
Zhang Mingli