A guy I used to work with said he worked for a company where all queries had to get approved by one of two full time DBAs - apparently with good reason as someone tried to modify a query that would have joined with half the rows in some gigantic table.
I worked at a place where only certain teams with a dedicated DBA were trusted to write direct queries (based on past incidents). All other teams had to ask a central DBA team to build stored procedures for any interaction with the database. If you think that this would create a huge backlog, you are correct... Non critical updates also needed to be coordinated with a "release train" where the code had to be ready 2 weeks before deployment due to the amount of testing it required. It was one of the major drivers behind an initiative to create micro services with separate databases that each team could do what they wanted with.
We ended up with a huge number of micro services and special orchestrator services to handle distributed transactions. But I guess that in a company of that scale, there are no perfect solution. At least we were able to make changes within minutes/hours instead of weeks.
Paradoxically we also got more pressure to deliver. In the past it was acceptable to leave a healthy buffer at the end of the scrum, to avoid missing the release train. This meant that we often spent the remaining buffer on refactoring, fixing small bugs that we felt we had time for or experimenting with POCs.
