Re: whether I can add a new encoding?

"=?ISO-8859-1?B?UGFuZG9yYQ==?=" <yeyukui@qq.com> writes:
> The pg_wchar.h file comments "We must avoid renumbering any backend encoding until libpq's major version number is
increasedbeyond 5", Can I add a new server-side encoding, GBK18030, and place it after PG_KOI8U in PG10.6? 

What is GBK18030?  If it's related to either GBK or GB18030,
then it'd be unsafe to use as a server encoding because it's not a
strict ASCII superset (that is, it has multibyte characters in
which not all bytes have the high bit set).  The lack of room for
a new server encoding in the pg_enc enum has seemed like a mostly
hypothetical problem because of that restriction.

            regards, tom lane