Range queries return fewer result after a lot of delete

Hi, I'm testing on the trunk version
I'm using : [cqlsh 2.3.0 | Cassandra 1.2.0-beta1-SNAPSHOT | CQL spec 3.0.0 | Thrift protocol 19.35.0]

My use case is :
I create a table
CREATE TABLE premier (
id int PRIMARY KEY,
value int
) WITH
comment='' AND
caching='KEYS_ONLY' AND
read_repair_chance=0.100000 AND
dclocal_read_repair_chance=0.000000 AND
gc_grace_seconds=864000 AND
replicate_on_write='true' AND
compression=

;

1) I insert 10 000 000 rows (they are like id = 1 and value =1)
2) I delete 2 000 000 rows (i use random method to choose the key value)
3) I do select * from premier ; and my result is 7944 instead of 10 000.
4) if if do select * from premier limit 20000 ; my result is 15839 .

So after a lot of delete, the range operator is not working.