I've noticed that in PostgreSQL 7.4, successive commands in a
transaction get cmin values that increment by 1, but in other
versions cmin increments by 2. Example:
CREATE TABLE foo (x integer);
BEGIN;
INSERT INTO foo VALUES (1);
INSERT INTO foo VALUES (2);
INSERT INTO foo VALUES (3);
COMMIT;
Results in 8.0.1 (same in 8.1devel, 7.3.9, 7.2.7):
SELECT xmin, cmin, x FROM foo;
xmin | cmin | x
------+------+---
7112 | 1 | 1
7112 | 3 | 2
7112 | 5 | 3
(3 rows)
Results in 7.4.7:
SELECT xmin, cmin, x FROM foo;
xmin | cmin | x
------+------+---
856 | 1 | 1
856 | 2 | 2
856 | 3 | 3
(3 rows)
What is 7.4 doing differently than the other versions?
--
Michael Fuhr
http://www.fuhr.org/~mfuhr/