Re: Support EXCEPT for ALL SEQUENCES publications

Hello!

+ if (footers[0] == NULL)
+ footers[0] = pg_strdup(tmpbuf.data);
+ else if (footers[1] == NULL)
+ footers[1] = pg_strdup(tmpbuf.data);
+ else
+ footers[2] = pg_strdup(tmpbuf.data);
+ resetPQExpBuffer(&tmpbuf);

Shouldn't the matching free calls also updated, this now leaks footers[2]?

+ "\n AND NOT EXISTS (\n"
+ " SELECT 1\n"
+ " FROM pg_catalog.pg_publication_rel pr\n"
+ " WHERE pr.prpubid = p.oid AND\n"
+ " pr.prrelid = '%s')"

Isn't a pr.prexcept check missing from this? It is included in other queries.

- /* EXCEPT clause is not supported with ALTER PUBLICATION */
- Assert(exceptseqs == NIL);
-

Would it be worth it to keep a more restricted assert, saying that
EXCEPT clause is only supported for ALTER PUBLICATION ... SET?