Sadrienne Posts - Convex Community

Sadrienne

•Created by Sadrienne on 3/11/2025 in #support-community

React & Query/bandwidth optimization

Just hoping for some clarification on what the best practice would be for what I want to achieve and get a bit more understanding of exactly how the subscriptions work and how to avoid re-reading data off the database too often. I have a pretty simple table structure of: - Category - Topic (contains an id field for the category it belongs to) - Message (contains an id field for the topic it belongs to) The goal is to display data for all topics in a category, which means reading from ~ 1000 documents to grab the data required at each level. All of the queries have indexes, but the way I'm currently doing it is generating a massive amount of bandwidth. Currently -- - a single useQuery is run at the top of the React document. - this query fetches the selected category data, then performs a search for all topic documents linked to that category id. The list of topic documents is then looped through to get a list of all messages related to that topic id. - all the fetched data is placed in an object that is then returned by the query. This lets me get a total count of messages per topic off the bat -- but if I'm reading things right, it also means that the entire query is being re-run whenever data changes (thus blowing out bandwidth). Is that correct? Would I be better off to break up the structure of the app itself and have each stage of the query run within the component? So: - Category data (fetch category information + topic list IDs, map through topic IDs and provide that to next component) - Topic data (use provided topic ID to fetch topic data + get related message IDs, provide message IDs to next component) - Message data (get + display message data) Will an approach like that mean that if just a piece of message data changes, only the component that the message has been fetched in will re-run? Or does a change to an item on the message table mean all queries related to the message table reruns? Will a change to something on the category table just cause the category query to react, or will it all retrigger because they're nested? What's the best pattern/practice here?

3 replies