Re: BUG #9210: PostgreSQL string store bug? not enforce check with correct characterSET/encoding

digoal(at)126(dot)com writes:
> select t, t::bytea from convert_from('\xeec1', 'sql_ascii') as g(t);
> [ fails to check that string is valid in database encoding ]

Hm, yeah. Normal input to the database goes through pg_any_to_server(),
which will apply a validation step if the source encoding is SQL_ASCII
and the destination encoding is something else. However, pg_convert and
some other places call pg_do_encoding_conversion() directly, and that
function will just quietly do nothing if either encoding is SQL_ASCII.

The minimum-refactoring solution to this would be to tweak
pg_do_encoding_conversion() so that if the src_encoding is SQL_ASCII but
the dest_encoding isn't, it does pg_verify_mbstr() rather than nothing.

I'm not sure if this would break anything we need to have work,
though. Thoughts? Do we want to back-patch such a change?

regards, tom lane