Tom Lane wrote: > More to the point, a GUC rollback transition *has to always > succeed*. Period. I was about to point out the exception of the transaction_read_only GUC, which according to the standard must not be changed except at the beginning of a transaction or a subtransaction, and must not be changed from "on" to "off" in a subtransaction. Then I noticed that, while we protect against an explicit change in a prohibited way, we allow a RESET: test=# begin transaction read only; BEGIN test=# select * from x; x --- 1 (1 row)
test=# set transaction_read_only = off; ERROR: transaction read-write mode must be set before any query test=# rollback; ROLLBACK test=# begin transaction read only; BEGIN test=# select * from x; x --- 1 (1 row) test=# reset transaction_read_only ; RESET test=# insert into x VALUES (2); INSERT 0 1 test=# commit; COMMIT I think that's a problem. It could allow back-door violations of invariants enforced by triggers, and seems to violate the SQL standard. I think this should be considered a bug, although I'm not sure whether it's safe to back-patch, given the change to existing behavior. Whether such a (required) exception to what you assert above should open the door to any others is another question. -Kevin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
