Is there a use case for a Salesforce-Postgres realtime bi-directional
synchronization tool? Is this something companies using Salesforce
would spend money on?Tools such as Heroku Connect[1] or Skyvia[2] provide this functionality but are
they being utilized?I was involved in a project that rebuilt Heroku Connect as a standalone tool.
Part of our reasoning for doing this:- Centralizing the update logic for external services into Salesforce,
- Having a better (i.e. SQL) method of querying Salesforce data,
- Saving costs on additional Salesforce seats as employees used external tooling instead, and
- Heroku Connect was found to be prohibitively extensive for our requirements.This was a Ruby/Rails shop so all updates went via ActiveRecord into
Postgres and then, via our tool, into Salesforce. Changes in Salesforce
triggered our tool to retrieved those changes and make the corresponding
updates in Postgres.Financially the company has offset the cost of maintenance against the
savings made by not having extra Salesforce seats and not paying for Heroku
Connect.Salesforce, of course, does not encourage this type of workflow (perhaps also the
reason why Heroku Connect is so expensive - Heroku being owned by Salesforce)
however it remains possible.[1] 
[2] 