I have a service running as a sidecar next to a variety of applications. This service needs to be extremely fast and do not make remote calls. It has to have in-memory database. The contents of this database have to be populated and kept up-to-date (although a lag is acceptable) with a central component. The service does not accept writes.
Of course this could be done through a mechanism of long pooling, for instance, but this brings the complexity of managing this solution and some intrinsic inefficiencies.
Is there a lightweight, ephemeral in-process and preferably in-memory database that can synchronise asynchronously with central replica preferably through regular HTTP so that no ports needs to be opened?