Details
-
Bug
-
Status: Open (View Workflow)
-
Major
-
Resolution: Unresolved
-
11.4.7, 11.8.3
-
None
-
OS: Ubuntu-20.04 LTS
Description
Isolation Level: Repeatable Read.
The SELECT statement does not create a snapshot when the WHERE condition evaluates to false.
/* init */ DROP TABLE IF EXISTS t; |
/* init */ CREATE TABLE t (c1 CHAR(1)); |
/* init */ INSERT INTO t(c1) VALUES ('A'); |
|
/* t1 */ BEGIN; |
/* t2 */ BEGIN; |
/* t2 */ SELECT * FROM t WHERE TIMESTAMPDIFF(MONTH,'2025-11-6','2025-11-11'); |
/* t1 */ DELETE FROM t WHERE TRUE; |
/* t2 */ INSERT INTO t(c1) VALUES ('B'); -- blocked |
/* t1 */ COMMIT; -- t2 unblocked |
/* t2 */ SELECT * FROM t ; -- [('B')] |
/* t2 */ COMMIT; |
The expectation is that transaction t2 will establish a snapshot at the first SELECT statement, so that the second SELECT statement can retrieve [('A'), ('B')]. However, in actual execution, the second SELECT statement in transaction t2 only retrieved [('B')] when the WHERE condition of the first SELECT statement was evaluated as false.