Build subscription logic

[manishrjain]

Build the equivalent of subscribe in GraphQL. So, users can subscribe to a query, and every time something changes, they'll automatically get an updated version of that response. This would be like streaming the results of a query.

[manishrjain]

A user should be able to specify a query, which would stream results back every time the corresponding data changes. The idea I have is this:

• Any server in the cluster gets this query.
• It identifies the predicates required to run this query.
• Identifies the servers serving these preds.
• Opens up GetUpdateStream request to these servers, with the list of preds.
• Every time it gets an updated ping from any of these servers, it sends off the query to be executed.
• It then compares the new result's hash with the previous result's hash.
• If they differ, it would stream the result back to the user.

This is a simple design, and it should achieve what we want here.

[jasonkuhrt]

I think what you're looking for is less subscribe and more live? https://dev-blog.apollodata.com/new-features-in-graphql-batch-defer-stream-live-and-subscribe-7585d0c28b07

[jasonkuhrt]

Would the following use-case be in-scope:

• Fetch a segment of users based on some property conditions
• may return millions of IDs on first result
• have any changes to this segment be streamed, just the delta