@Folcon in my experience, the fulltext support in On-Prem won’t get you very far (it’s very limited in how you can customize it) and you’re likely to want to offload fulltext seach to a more capable engine anyway; so I wouldn’t make that the decisive factor between On-Prem and Cloud. You should rather think about your operational requirements and architecture to decide.
Regardless of whether you use On-Prem or Clould:
- Datomic makes it unusually straighforward to sync derived data to specialized stores such as ElasticSearch, because the Log API makes change detection very easy. A basic but often effective approach can be to periodically update the derived store in batches, by computing the set of entities affected by recent changes, and (re-)computing the documents for those.
- Setting up a production-ready ElasticSearch on AWS is a bit of an investment, so you may want to start with something more managed.