@app.callback improvements? (Trigger component, same Output multiple times, callback without Output, serverside store / callback cache)

[fohrloop]

@Emil

As you note, this short-circuit concept is restricted to callbacks the have only ServerInput s. How often will this actually happen? Do you have any examples? In most cases, i guess you will need inputs from the client.

The simple example is what people seem to want to do (for example this):

• Press a button
• Calculate dataframe df server side, based on some selection in frontend
• Save that df into temporary memory my-memory
• Have multiple callbacks listening my-memory. Let’s say, there are 4 Graphs created and shown to user from 4 different callbacks.

In this case, when multiple callbacks listen to the my-memory, there will be normally many unnecessary HTTP requests for the server and sending (data with dcc.Store, session ID with ServerStore) back and forth. This all could, in theory, be short-circuited in such way that the session ID is only sent to the server once.

@Emil

I am not sure how large a speed increase you would actually enable as compared to just keeping the data on server (as i do now).

On local machine, perhaps quite negligible speed increase, but if you put your app to a slow cheap server (free tier heroku), I guess the speed gain should be visible. But yeah, some benchmarking and testing could be before implementation, to make sure there is really notable potential performance increase.