How to use different datasource of one microservice with multi instances

Question

I'm working on a microservices architecture using Spring boot, my microservice A uses MySQL as a primary datasource I'm wondering could I make an instance of A and change datasource of that instance to MongoDB?

Why I would do that? well basically I'll have an endpoint which will handle a file uploads of million lines so I wish to have 2 datasources of that microservice.

Or should I duplicate A to another microservice B and use MongoDb as datasource and make a specific rest api?

Answer 1

If you use ORM (and I believe you using it) you have to create a model for both databases, because of the different concepts of MySQL and MongoDB, you have different sets of annotations. For example, for MongoDB you must use @Document instead of an @Entity. If only your service A targets this file uploads functionality - you can implement it together in one service. If you have to make uploads from multiple services or if it makes sense to have separate scaling for service A functionality and file upload feature - make it a separate service for uploads. In most cases, the second way is more attractive because it allows avoiding service duty separation in two services when you have requirements changes