Skip some CalculationsTests

[alimi]

Most of the skipped tests fail against CockroachDB because ActiveRecord strips out the query order clause from group by queries making it impossible to guarantee the results order. These tests pass against databases like PostgreSQL because they'll inherently order by the group by clause. This appears to be a bug in ActiveRecord, see rails/rails#38936.

The other test, :test_group_by_with_order_by_virtual_count_attribute, fails because ordering with virtual count attributes doesn't work against CockroachDB.

For example, here’s a posts table and it has a type column.

activerecord_unittest=# select posts.type, count(*) from posts group by posts.type;
    type     | count 
-------------+-------
 Post        |     9
 StiPost     |     1
 SpecialPost |     1
(3 rows)

If I run a query like SELECT MAX(posts.comments_count) AS maximum_comments_count, posts.type AS posts_type FROM posts GROUP BY posts.type ORDER BY posts.count ASC limit 2; against PostgreSQL, it works.

activerecord_unittest=# SELECT  MAX(posts.comments_count) AS maximum_comments_count, posts.type AS posts_type FROM posts GROUP BY posts.type ORDER BY posts.count ASC limit 2;
 maximum_comments_count | posts_type  
------------------------+-------------
                      2 | StiPost
                      1 | SpecialPost
(2 rows)

When I run the query against CockroachDB, it blows up because posts.count isn’t recognized in the ORDER BY clause.

root@localhost:26258/activerecord_unittest> SELECT  MAX(posts.comments_count) AS maximum_comments_count, posts.type AS posts_type FROM posts GROUP BY posts.type ORDER BY posts.count ASC limit 2;
ERROR: column "posts.count" does not exist

Is this a know limitation in CockroachDB? I’m not seeing it documented anywhere (it’s kinda hard to search for).

[alimi]

@rafiss opened cockroachdb/cockroach#47477 for the ordering with virtual count attributes failure.

[apantel]

This is fine, just clean up the commits.

[alimi]

What do you mean by clean up the commits?