I’d love to hear more about how you solved the synchronization process, if you’d be willing to share. How do you handle conflicting changes, like local and remote both changing the same field, or one deleting a resource while another modified it?
I’m trying to understand more real world examples of syncing offline with online.
I regret to report that I am not doing anything especially clever (e.g., CRDT). In some cases, I am doing things that are expensive in terms of storage, bandwidth, or local computation to facilitate synchronization.
Basically, my schema design prohibits use of UPDATE and requires that every row have a timestamp. The clients maintain a synchronization log to ensure they have fetched every available row. The keep track of which rows have not yet been sent up to the server.
This means that finding the current state of things that can change means doing a "SELECT column ORDER by timestamp DESC LIMIT 1" in order to see the latest state and always doing INSERT instead of UPDATE to update state.
In some cases, I am storing a delta in a row instead of a complete state representation. This means that some views have to replay the changes to show the current state. I cache the result of these.
I do some general high level caching on the client side to make all of this as fast as possible. I have watchdogs set on the local GUI to warn me when latency of the GUI event loop is over 200 milliseconds. I use these warnings to focus effort on caching and other optimizations.
I’m trying to understand more real world examples of syncing offline with online.
Thanks!