It doesn't look like this is currently possible in Retool. I'm curious what your use case is here, would you mind giving some context for how you'd be using sync and what makes it particularly handy?
Not sure if something has changed between now and when originally asked - but sync changes appears to work just fine now.
I achieved it like so:
and then in my app i simply added the PouchDB library via CDN:
Now - as I add/modify anything in my CouchDB database from any other tools/programs, retool will reflect those changes and data immediately. Quite nice!
I'm using CouchDB as a 'connector' between some old legacy On prem software/databases and retool. Now i can have the on prem software simply update the couchDB database, and retool automatically picks up the changes and can act accordingly, in real time.