wrong query result in presence of a unique index

• Key: DERBY-3288
• Type: Bug
• Status: Resolved
• Resolution: Fixed
• Priority: Major
• Assignee: A B
• Reporter: Gerald Khin
• Component/s: SQL
• Affects Version/s: 10.2.1.6, 10.2.2.0, 10.3.1.4, 10.3.2.1, 10.4.1.3
• Fix Version/s: 10.3.3.0, 10.4.1.3

Description

The DDL to reproduce the bug is:

CREATE TABLE tab_a (PId BIGINT NOT NULL);

CREATE TABLE tab_c (Id BIGINT NOT NULL PRIMARY KEY, PAId BIGINT NOT NULL, PBId BIGINT NOT NULL);

INSERT INTO tab_c VALUES (91, 81, 82);
INSERT INTO tab_c VALUES (92, 81, 84);
INSERT INTO tab_c VALUES (93, 81, 88);
INSERT INTO tab_c VALUES (96, 81, 83);

CREATE TABLE tab_v (OId BIGINT NOT NULL , UGId BIGINT NOT NULL, val CHAR(1) NOT NULL);
CREATE UNIQUE INDEX tab_v_i1 ON tab_v (OId, UGId, val);
CREATE INDEX tab_v_i2 ON tab_v (UGId, val, OId);

INSERT INTO tab_v VALUES (81, 31, 'A');
INSERT INTO tab_v VALUES (82, 31, 'A');
INSERT INTO tab_v VALUES (83, 31, 'A');
INSERT INTO tab_v VALUES (84, 31, 'A');
INSERT INTO tab_v VALUES (85, 31, 'A');
INSERT INTO tab_v VALUES (86, 31, 'A');
INSERT INTO tab_v VALUES (87, 31, 'A');
INSERT INTO tab_v VALUES (81, 32, 'A');
INSERT INTO tab_v VALUES (82, 32, 'A');
INSERT INTO tab_v VALUES (83, 32, 'A');
INSERT INTO tab_v VALUES (84, 32, 'A');
INSERT INTO tab_v VALUES (85, 32, 'A');
INSERT INTO tab_v VALUES (86, 32, 'A');
INSERT INTO tab_v VALUES (87, 32, 'A');

CREATE TABLE tab_b (Id BIGINT NOT NULL PRIMARY KEY, OId BIGINT NOT NULL);

INSERT INTO tab_b VALUES (141, 81);
INSERT INTO tab_b VALUES (142, 82);
INSERT INTO tab_b VALUES (143, 84);
INSERT INTO tab_b VALUES (144, 88);
INSERT INTO tab_b VALUES (151, 81);
INSERT INTO tab_b VALUES (152, 83);

CREATE TABLE tab_d (Id BIGINT NOT NULL PRIMARY KEY, PAId BIGINT NOT NULL, PBId BIGINT NOT NULL);

INSERT INTO tab_d VALUES (181, 141, 142);
INSERT INTO tab_d VALUES (182, 141, 143);
INSERT INTO tab_d VALUES (186, 151, 152);


The query returning the wrong result is:

SELECT tab_b.Id
FROM tab_b JOIN tab_c ON (tab_b.OId = tab_c.PAId OR tab_b.OId = tab_c.PBId)
LEFT OUTER JOIN tab_a ON tab_b.OId = PId
WHERE EXISTS (SELECT 'X' FROM tab_d WHERE (PAId = 141 AND PBId = tab_b.Id) OR (PBId = 141 AND PAId = tab_b.Id))
  AND EXISTS (SELECT 'X' FROM tab_v WHERE OId = tab_b.OId AND UGId = 31 AND val = 'A')

The result should consist of two rows (142),(143), but it returns only one row (142).

The correct result would be returned if the index tab_v_i1 had been created as non-unique.

The correct result would also be returned if the condition ...AND val='A' had been replaced by ...AND val='A' || ''.