I don't know what you mean by plugin, but I guess it may be related to a mobile app...
What about having a worker service in the background and let these instances to communicate with the service?
In this case the instances can send SQL commands and receive the result in asynchronous mode. They will also be able to write to the database, and the app will use way less disk space and less writes too.
This scales very well too, as you can have many instances communicating to the service (worker thread).
You just need to figure out the communication method, data serialization, etc. But it may have some examples on the internet of something similar.