Hello.

The question is: does Slony correctly support DEFERRABLE foreign keys during
the replication?

Suppose I have a table with deferrable foreign key constraint referenced to
self:

tbl(id INTEGER, parent_id INTEGER);

The field parent_id references to the table tbl with deferrable constraint:

ALTER TABLE tbl ADD CONSTRAINT parent FOREIGN KEY (parent_id)
REFERENCES tbl(id) DEFERRABLE INITIALLY DEFERRED;

Then I insert a child element in tbl BEFORE inserting a parent one:

BEGIN;
INSERT INTO tbl(id, parent_id) VALUES(1, 2);    -- child first!
INSERT INTO tbl(id, parent_id) VALUES(2, null);  -- parent
COMMIT;

It is correct, because the constraint is deferrable and checked at the end
of transaction.

But I suppose that in the event log this two INSERTs will possibly (?) be
presented one after one and in DIFFERENT trtansactions, so, the first one
will fail with constraint check error immediately. Please say, could it
happen or not? Or, if some statements were initially in a single
transaction, slon daemon will run them in a single transaction too on a
replica?

P.S.
Please do not advice to change the order of INSERTs, because in a real
application I run these inserts as:
INSERT INTO tbl(id, parent_id) SELECT * FROM othertbl;
and the order is totally unpredictable.
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