Hi, The documentation states that postgres_fdw can be used with remote servers as far back as PostgreSQL 8.3. https://www.postgresql.org/docs/devel/postgres-fdw.html#POSTGRES-FDW-CROSS-VERSION-COMPATIBILITY
However, when using PostgreSQL 9.4 or earlier as a remote server, INSERT ON CONFLICT on a foreign table fails because this feature is only supported in v9.5 and later. Should we add a note to the documentation to clarify this limitation? For example: "Another limitation is that when executing INSERT statements with an ON CONFLICT DO NOTHING clause on a foreign table, the remote server must be running PostgreSQL 9.5 or later, as earlier versions do not support this feature." Regards, -- Fujii Masao Advanced Computing Technology Center Research and Development Headquarters NTT DATA CORPORATION
