postgresql 10 support for GitLab
GitLab currently uses rails 4.2, which doesn't work with PostgresSQL 10: https://github.com/rails/rails/issues/28780
Rails aren't taking the patch to add support, but we can backport it until the efforts to upgrade GitLab to rails 5 are completed (see https://gitlab.com/gitlab-org/gitlab-ce/issues/14286 )
We still ship 9.6 in omnibus and this is unlikely to change in the very near future, but supporting 10.0 will help people who use other environments (SaaS deployments, install from source, etc).
Some ~Geo use cases may also benefit from pg 10:
- https://gitlab.com/gitlab-org/gitlab-ee/issues/4597
- https://gitlab.com/gitlab-org/gitlab-ee/issues/4491 (fix introduces code conditional on pg 10.0 being installed)
I propose we just introduce the backport and mentioned in that issue and ensure the specs all pass against pg 10.0 once.
We currently test against the lowest supported version of postgresql (9.2), so this is consistent with existing policy. It would be nice to test against every supported version, but our CI takes too long to run for that to be feasible.
/cc @stanhu