On Mon, Jul 25, 2022 at 11:39 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
PG Bug reporting form <noreply@postgresql.org> writes: > In PostgreSQL 15 beta, when I try to insert a NULL value which violates a > "UNIQUE NULLS NOT DISTINCT" constraint, PostgreSQL will get stuck in an > endless loop if the command includes an "ON CONFLICT" clause.
> CREATE TABLE test (val TEXT UNIQUE NULLS NOT DISTINCT); > INSERT INTO test (val) VALUES ('a') ON CONFLICT DO NOTHING; -- inserts 'a' > INSERT INTO test (val) VALUES ('a') ON CONFLICT DO NOTHING; -- does > nothing > INSERT INTO test (val) VALUES (NULL) ON CONFLICT DO NOTHING; -- inserts > NULL > INSERT INTO test (val) VALUES (NULL) ON CONFLICT DO NOTHING; -- > unresponsive
Yup, still a problem in HEAD. It correctly reports an error if you just "INSERT INTO test (val) VALUES (NULL)", but something in the ON CONFLICT code path seems not to be on board with this. Peter?
Yeah, I can see the same problem. _bt_check_unique() can catch violation of unique index constraint successfully, so insert without 'ON CONFLICT' has no problem. But ExecCheckIndexConstraints() fails to tell the NULL tuple violates unique constraint, and the logic below is quite suspicious to me.
/* * If any of the input values are NULL, the constraint check is assumed to * pass (i.e., we assume the operators are strict). */ for (i = 0; i < indnkeyatts; i++) { if (isnull[i]) return true; }
