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Sylvain Lebresne commented on CASSANDRA-5457:
---------------------------------------------
I'm afraid this has to do with the fact that clustering order doesn't do what
you think. Namely, it should just be seen as an "hint" to the storage engine
that basically says "I will do most of my queries with field1 in descending
order so optimize for that". So in particular, it doesn't give you any
particular guarantee on the sort order of queries, you still have to use ORDER
BY in the query for that (and as it happens, you won't be allowed to order on
'field1' unless you specify 'id' because we have no way to do that efficiently).
I'll not that if you did a query like:
{noformat}
SELECT * FROM reverse_sort_test WHERE id=0;
{noformat}
and that was returning multiple results, then those result would be ordered by
descending field1, while it would be in ascending order if you don't add the
clustering order during the definition. *But*, that's just CQL3 using the fact
you haven't specify any ORDER BY for your query to return the result in the
order that is the easier.
> Ordering is ignored when using 'CLUSTERING ORDER BY'
> -----------------------------------------------------
>
> Key: CASSANDRA-5457
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5457
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 1.2.4
> Reporter: Patrick McFadin
> Assignee: Sylvain Lebresne
>
> Creating the following table:
> create table reverse_sort_test (
> id int,
> field1 int,
> field2 int
> PRIMARY KEY (id, field1, field2)
> ) WITH CLUSTERING ORDER BY (field1 DESC);
> I would expect field1 to be reverse ordered.
> Inserting this data:
> insert into reverse_sort_test (id,field1,field2) values (1,1,1);
> insert into reverse_sort_test (id,field1,field2) values (3,3,3);
> insert into reverse_sort_test (id,field1,field2) values (2,2,2);
> insert into reverse_sort_test (id,field1,field2) values (4,4,4);
> insert into reverse_sort_test (id,field1,field2) values (6,6,6);
> insert into reverse_sort_test (id,field1,field2) values (5,5,5);
> And running a select:
> select * from reverse_sort_test;
> id | field1 | field2
> ----+--------+--------
> 5 | 5 | 5
> 1 | 1 | 1
> 2 | 2 | 2
> 4 | 4 | 4
> 6 | 6 | 6
> 3 | 3 | 3
> The order looks random.
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