This reverts commit 537ac7d6ad, reversing
changes made to 9c9c54abe0.
Reason:
The way we preload associations will change the meaning of GROUP BY
operations. This is illustrated in the SQL generated by the added
test (failing on PG):
Association Load:
D, [2015-12-21T12:26:07.169920 #26969] DEBUG -- : Post Load (0.7ms) SELECT "posts".* FROM "posts" LEFT JOIN comments ON comments.post_id = posts.id WHERE "posts"."author_id" = $1 GROUP BY posts.id ORDER BY SUM(comments.tags_count) [["author_id", 1]]
Preload:
D, [2015-12-21T12:26:07.128305 #26969] DEBUG -- : Post Load (1.3ms) SELECT "posts".* FROM "posts" LEFT JOIN comments ON comments.post_id = posts.id WHERE "posts"."author_id" IN (1, 2, 3) GROUP BY posts.id ORDER BY SUM(comments.tags_count)
b06f6a1d8c