The Job ID is defined by the storage engine. In the case of the SQL Server storage engine, it is defined by the identity constraint:
As for the Redis storage engine, it is closed source so I can’t say for sure and you can’t just fork / override it. (Unless you get access to the source code as a premium user ?) If it’s anything like the open-source version of the engine, it would be pretty easy to modify it in order to make it configurable - But it is storage engine specific:
We have a requirement where we need to fetch the jobid from the queue on a priority basis using redis. We have found a solution to reorder the jobs within the queue if we know the jobid. And this jobid needs to be defined by the user instead of generating it dynamically by the Redis.