Fridtjof Sander created CASSANDRA-13657:
-------------------------------------------
Summary: Materialized Views: Index MV on TTL'ed column produces
orphanized view entry if another column keeps entry live
Key: CASSANDRA-13657
URL: https://issues.apache.org/jira/browse/CASSANDRA-13657
Project: Cassandra
Issue Type: Bug
Components: Materialized Views
Reporter: Fridtjof Sander
```
CREATE TABLE t (k int, a int, b int, PRIMARY KEY (k));
CREATE MATERIALIZED VIEW mv AS SELECT * FROM t WHERE k IS NOT NULL AND a IS NOT
NULL PRIMARY KEY (a, k);
INSERT INTO t (k) VALUES (1);
UPDATE t USING TTL 5 SET a = 10 WHERE k = 1;
UPDATE t SET b = 100 WHERE k = 1;
SELECT * from t; SELECT * from mv;
k | a | b
---+----+-----
1 | 10 | 100
(1 rows)
a | k | b
----+---+-----
10 | 1 | 100
(1 rows)
-- 5 seconds later
SELECT * from t; SELECT * from mv;
k | a | b
---+------+-----
1 | null | 100
(1 rows)
a | k | b
----+---+-----
10 | 1 | 100
(1 rows)
-- that view entry's liveness-info is (probably) dead, but the entry is kept
alive by b=100
DELETE b FROM t WHERE k=1;
SELECT * from t; SELECT * from mv;
k | a | b
---+------+------
1 | null | null
(1 rows)
a | k | b
----+---+-----
10 | 1 | 100
(1 rows)
-- deleting the base-entry doesn't help, because the view-key can not be
constructed anymore (a=10 already expired)
```
The problem here is that although the view-entry's liveness-info (probably)
expired correctly a regular column (`b`) keeps the view-entry live. It should
have disappeared since it's indexed column (`a`) expired in the corresponding
base-row. This is pretty severe, since that view-entry is now orphanized.
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