Re: Regression tests fail on OpenBSD due to low semmns value

Hello Tom,

16.12.2024 07:23, Tom Lane wrote:
> Alexander Lakhin<exclusion(at)gmail(dot)com> writes:
>
>> ...
>> So GetSafeSnapshot() waits indefinitely for possibleUnsafeConflicts to
>> become empty (for other backend to remove itself from the list of possible conflicts
>> inside ReleasePredicateLocks()), but it doesn't happen.
> This seems like an actual bug?

I've reproduced this behavior with two reduced sqls.
prepared_xacts.sql:
BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
  CREATE TABLE pxtest4 (a int);
PREPARE TRANSACTION 'regress_sub2';
\c -
COMMIT PREPARED 'regress_sub2';
-- the script ends prematurely and doesn't reach COMMIT when \c fails due
-- to the "too many clients" error.

transactions.sql
SELECT pg_sleep(1);
CREATE TABLE writetest (a int);

BEGIN;
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE, READ ONLY, DEFERRABLE; -- ok
SELECT * FROM writetest; -- ok
COMMIT;

and parallel_schedule:
test: transactions prepared_xacts

So "transactions" backend just waits for the prepared transaction to
finish.

19.12.2024 01:06, Tom Lane wrote:
> We'd still want to make the other changes I mentioned for NetBSD's
> sake, though.

Thank you for fixing that shortcoming!

Best regards,
Alexander