Well you are also using a strategy that is not really well defined for tenancy. I guess the question is whether multi-tenancy should utilize a different set of generators.

For table, its probably pretty trivial to rig in the concept of tenancy since we could just add a new column to hold the tenant_id when multi-tenancy is in effect.

Or, as you say, a more general purpose solution would be to hold a distinct optimizer per tenant in memory.