The following bug has been logged on the website:
Bug reference: 11919
Logged by: Gavin Panella
Email address: gavin.panella@canonical.com
PostgreSQL version: 9.3.5
Operating system: Ubuntu 12.04
Description:
I think I might have found a bug in PostgreSQL 9.3.5 relating to
serializable isolation, where code running within a savepoint can see
data committed in a second session after the commencement of the first,
but that data then "disappears" when the savepoint is rolled-back.
Of course, my understanding may be the bug, but here's how to reproduce
the effect:
1. Open two psql sessions to the same database.
2. Create an example table:
create table things (a int unique);
3. In the first session:
begin isolation level serializable;
insert into things (a) values (1);
Don't commit yet.
4. In the second session:
begin isolation level serializable;
savepoint one;
insert into things (a) values (1);
This should hang.
5. In the first session:
commit;
6. Go back to the second session. It will have failed with:
ERROR: duplicate key value violates unique constraint "things_a_key"
DETAIL: Key (a)=(1) already exists.
7. Continue in the second session:
rollback to savepoint one;
select * from things;
You should see:
a
---
(0 rows)
