Drop "projects"."ci_id" column
We're hitting into a number of bugs trying to use this column. Just search from Google with "GitLab" and "ci_id" could give some of them. Here's some quick examples: #15005 (closed), #21574 (closed), #22296 (closed), etc.
Most of them were related to deleting the project, because in order to delete a particular build, we're also depending on this column. However, at the time we're trying to delete the build, the project is often already scheduled to be deleted, therefore considered unavailable. This is somehow a circular dependency.
Yet another recent fix was !8960 (merged), which @ayufan also mentioned that:
I wish we could drop
ci_id
. It would be relief.
This is the issue to track this.
Note that this as far as I know, is already deprecated a long time ago, reading from the code comments.