Arvados

Hi:
We developed some db optimizations for arkau to avoid high load episodes on that instance (the other ones doesn't need this active). Those were applied in production in 3.2.0 and worked well, when upgrading to 3.2.1 those were overwritten in the update and we had some high-load the following day.

We thought these could be related to heavy managed_permissions churn + outdated scheduler statistics, but we also had a daily statistics refresh, so the scheduler has more issues than that. Also we should definitely deploy Postgres 18 on arkau, but didn't get to that yet.

After reapplying those patches we didn't see a repeat. The users.rb is the critical one, since workflow.rb onbly affects the workflow selection functionality.

Could you incorporate those or equivalent modifications in the production version?