Hi Hackers
I have noticed an issue with deferrable triggers not always being
deferrable. Eg:
alter table subsession
add constraint fk_subsession_session foreign key (session_id)
references session (session_id)
deferrable;
alter table subsession2
add constraint fk_subsession2_session foreign key (session_id)
references session (session_id)
on delete restrict on update restrict
deferrable;
select tgconstrname, tgtype, tgenabled, tgdeferrable, tginitdeferred
from pg_trigger where tgisconstraint;
tgconstrname | tgtype | tgenabled | tgdeferrable |
tginitdeferred
------------------------+--------+-----------+--------------+----
fk_subsession_session | 21 | t | t | f
fk_subsession_session | 9 | t | t | f
fk_subsession_session | 17 | t | t | f
fk_subsession2_session | 21 | t | t | f
fk_subsession2_session | 9 | t | f | f
fk_subsession2_session | 17 | t | f | f
So it would seem that if I include the clauses:
on delete restrict on update restrict
Then the 'deferrable' which follows is only applied to creates and
not to updates or deletes.
Since 'restrict' is the default, the clauses aren't adding any value
and can be omitted. In my case, the SQL is generated for me by
PowerDesigner. My workaround is to tweak the PowerDesigner output
definition to not include this line.
I have seen this behaviour in both 7.2 and 7.3. Is it a bug? Or
am I misunderstanding something?
Regards
Grant
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