Basically could someone provide a more technical explanation of this?
It says that it watches(subscribes to) for block headers and when comes in it "through the transactions looking to see if any of them touched our contracts". How does it do this? Does it have to retrieve all the transactions in the block, or is there some clever way for it to know this (a merkle proof or something?)?
It then says "we replay the calls already in the store to refresh any potentially altered data." How do you 'replay a call'? Does that mean it simulates the call, or it fetches the data from the blockchain for every value drizzle is subscribed to?
Lastly (hopefully explaining the above will make this question redundant), how does this scale? If you are watching 100 contract values does that make 100x more calls to the blockchain every block than if you are only subscribed to 1 value?