Just looking at the code the method `getTenantMigrationAccessBlockerForDbName()` may return a wrong blocker.

Example: if we have unrelated tenants 'joe' and 'joe_doe' requesting a blocker for DB that belongs to tenant 'joe_doe' and has prefix 'joe_doe_' may actually return a first blocker for tenant 'joe' because the literal prefix 'joe_' will match the DB name.