Database Reviews

* [x] https://gitlab.com/gitlab-org/gitlab-ee/issues/5348#note_142649706
* [x] @NikolayS https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25230#note_142474150
* [x] @NikolayS https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25278#note_142134862
* [x] @NikolayS https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21197#note_139607418
* [x] @NikolayS https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25107#note_140670702 (Nik: checking it on a "restore" box)
* [x] https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25182#note_143426559
* [x] @NikolayS https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25432#note_143741434
* [x] @NikolayS https://gitlab.com/gitlab-org/gitlab-ce/issues/57284#note_143632158
* [x] @NikolayS https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7361#note_143467417
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25417#note_145035983
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9283
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9468#note_145050418
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/issues/57873
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25474#note_145490484
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9625
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9663
* [x] @yguo https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9593#note_144222817
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/7361
* [x] @NikolayS https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9544#note_144868675
* [x] @yguo https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9572#note_145028420
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9744
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9468#note_145290166
* [x] @NikolayS https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25639
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25532#a46973a5817634d9469930bacdf06d22045ac89b
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_request/9807#2cda0c6171fa7d04989507a1dd112e34c40df46d_220_219
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25532
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9833
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9841
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25533#note_146516657
* [x] @yguo  https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25437#note_146925022
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25034
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9858#a45f971bfca57680d3204229f43425fe162dc9c3
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25181
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9786#note_148357464
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25806
* [x] @abrandl https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25533#2d53eb4595665098858367d6ea2b62c548d55d0a
* [ ] @abrandl Rails 5.1 https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9386

Story points: 8.0