The second fdw cannot be postgres_fdw or everything will work as expected. I thought the problem was in multicorn until I started getting requests for a ctid column. Which hints at it being somewhere in postgres, most likely the fdw. It's not important, but I thought you would like to know.
Ross
On Thu, Aug 3, 2017 at 11:52 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
rbiro@interfacefinancial.com writes: > Using postgres_fdw seems to assume that the foreign table is not also a > foreign table in the remote db.
> Symptoms: connections closing with little or no error message, requesting > ctid from a foreign table that doesn't have a ctid, even dataloss iin one > instance*.
> Reproduce: create two Postgresql databases, a and b. Create a foreign table > in a using a fdw other than postgres_fdw. Multicorn is a good choice since > it is then easy to see everything.
Without a concrete test case, it's really hard to prove anything about this, or even to tell which component the problem is in. But a desultory test using two levels of postgres_fdw seemed to work, which suggests that you need to take this up with the multicorn authors.
contrib_regression=# create table base (a int, b text); CREATE TABLE contrib_regression=# create foreign table level1 (a int, b text) server loopback options(schema_name 'public', table_name 'base'); CREATE FOREIGN TABLE contrib_regression=# create foreign table level2 (a int, b text) server loopback options(schema_name 'public', table_name 'level1'); CREATE FOREIGN TABLE contrib_regression=# insert into level2 values(42, 'foo'); INSERT 0 1 contrib_regression=# select * from base; a | b ----+----- 42 | foo (1 row) contrib_regression=# update level2 set b = 'bar' where a = 42; UPDATE 1 contrib_regression=# select * from base; a | b ----+----- 42 | bar (1 row)
CONFIDENTIALITY NOTICE: This email message, including any attachments, is for the sole use of the intended recipient/s and may contain confidential & privileged information. Any unauthorized review, use, disclosure, or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original messages and any attachments.
