| # Two IDs test |
| # |
| # Small, simple test showing read-only anomalies. |
| # |
| # There are only four permutations which must cause a serialization failure. |
| # Required failure cases are where s2 overlaps both s1 and s3, but s1 |
| # commits before s3 executes its first SELECT. |
| # |
| # If s3 were declared READ ONLY there would be no false positives. |
| # With s3 defaulting to READ WRITE, we currently expect 12 false |
| # positives. Further work dealing with de facto READ ONLY transactions |
| # may be able to reduce or eliminate those false positives. |
| |
| setup |
| { |
| create table D1 (id int not null); |
| create table D2 (id int not null); |
| insert into D1 values (1); |
| insert into D2 values (1); |
| } |
| |
| teardown |
| { |
| DROP TABLE D1, D2; |
| } |
| |
| session s1 |
| setup { BEGIN ISOLATION LEVEL SERIALIZABLE; } |
| step wx1 { update D1 set id = id + 1; } |
| step c1 { COMMIT; } |
| |
| session s2 |
| setup { BEGIN ISOLATION LEVEL SERIALIZABLE; } |
| step rxwy2 { update D2 set id = (select id+1 from D1); } |
| step c2 { COMMIT; } |
| |
| session s3 |
| setup { BEGIN ISOLATION LEVEL SERIALIZABLE; } |
| step ry3 { select id from D2; } |
| step c3 { COMMIT; } |
