We dropped MySQL support and a lot of mysql specific code has been
removed in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/29608.

This comes in from the other direction and removes any `if postgresql?`
branches.

vshushlin authored 5 years ago and Nick Thomas committed 5 years ago

- Set access level in before_validation hook
- Add post migration for updating existing project_features

Adds `# frozen_string_literal: true` to spec/models ruby files

This will allow an explicitly-disabled feature flag to override a
feature being available for a project.

As an extreme example, we could quickly disable issues across all
projects at runtime by running `Feature.disable(:issues)`.

We started syncing all the wiki regardless of the fact it's disabled or
not. We couldn't do that in one stage because of needing of smoth update
and deprecating things. This is the second stage that finally removes
unused columns in the geo_node_status table.

This method used to use a UNION, which would lead to it performing the
same query twice; producing less than ideal performance. Further, in
certain cases ActiveRecord could get confused and mess up the variable
bindings, though it's not clear how/why exactly this happens.

Fortunately we can work around all of this by building some of the WHERE
conditions manually, allowing us to use a simple OR statement to get all
the data we want without any of the above problems.

https://gitlab.com/gitlab-org/gitlab-ce/issues/24007