"=?gb18030?B?U2FsYWRpbg==?=" <jiaoshunt...@highgo.com> writes: > The output i expected: > pg_largeobject_metadata and pg_largeobject in both database A and database > B should have rows.Shouldn't only in database A.So, i can use large object > functions > to operate large_objectin remote table or foreign table.
The big picture here is that Postgres is a hodgepodge of features that were developed at different times and with different quality standards, over a period that's now approaching forty years. Some of these features interoperate better than others. Large objects, in particular, are largely a mess with a lot of issues such as not having a well-defined garbage collection mechanism. They do not interoperate well with foreign tables, or several other things, and you will not find anybody excited about putting effort into fixing that. We're unlikely to remove large objects altogether, because some people use them successfully and we're not about breaking cases that work today. But they're fundamentally incompatible with use in foreign tables in the way you expect, and that is not likely to get fixed. regards, tom lane