This article is part 4 of a short series of questions. See the full series here.
When building software, I like to make sure that I’ve the correct indexes are added and the query is correctly configured to eager load associations to reduce or prevent N+1 queries. Typically, I’ve used the bullet gem for this in the past.
For the next step, when dealing with large amounts of data, I’d make sure I’m not loading everything into memory by batching items with find_each instead of just each, for example. Focusing on the each example, I’d then look at view caching, which would prevent a database hit from even happening — not hitting the database is the best database optimisation of all.
In terms of tools, I know a lot of these types of code changes get caught by linters and automic code reviews in Code Climate for example. I don’t typically use these directly in my local coding environment because I like to focus directly on the problem I’m solving rather than fighting with linters (although, I’m happy to alter after the fact).