In this Hasty Treat, Scott and Wes talk about a common problem you'll encounter in your development career — the n+1 problem.
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05:00 - What is the n+1 problem?
- The N+1 problem can happen in any language but is especially prevalent in GraphQL because it's so easy to query relationships.
09:33 - The solution
- The solution to the n+1 problem is to batch the queries. As you loop over each podcast, keep an array of host IDs to lookup. Once you have looped over the podcasts, make a single query to the database with your large array of podcast host Ids.
11:11 - Should you care?
- Sometimes no: its often fine to do multiple DB Calls
- Facebook DataLoader
- Many ORMs take care of this for you
- Prisma N+1: https://www.youtube.com/watch?v=7oMfBGEdwsc&vl=en
- Mongoose Populate
- Apollo Studio