Normal Description
As noted on CASSANDRA-6875, the tuple notation is broken when the clustering order mixes ASC and DESC directives because the range of data they describe don't correspond to a single continuous slice internally. To copy the example from CASSANDRA-6875:
cqlsh:ks> create table foo (a int, b int, c int, PRIMARY KEY (a, b, c)) WITH CLUSTERING ORDER BY (b DESC, c ASC); cqlsh:ks> INSERT INTO foo (a, b, c) VALUES (0, 2, 0); cqlsh:ks> INSERT INTO foo (a, b, c) VALUES (0, 1, 0); cqlsh:ks> INSERT INTO foo (a, b, c) VALUES (0, 1, 1); cqlsh:ks> INSERT INTO foo (a, b, c) VALUES (0, 0, 0); cqlsh:ks> SELECT * FROM foo WHERE a=0; a | b | c ---+---+--- 0 | 2 | 0 0 | 1 | 0 0 | 1 | 1 0 | 0 | 0 (4 rows) cqlsh:ks> SELECT * FROM foo WHERE a=0 AND (b, c) > (1, 0); a | b | c ---+---+--- 0 | 2 | 0 (1 rows)
The last query should really return (0, 2, 0) and (0, 1, 1).
For that specific example we should generate 2 internal slices, but I believe that with more clustering columns we may have more slices.