One row, many threads: How to avoid database duplicates in Rails applications

Making sure each database row is unique, and tables contain no duplicates seems like a straightforward task in Rails. Active Record has a built-in validator that you can put on a model and call it a day. Until your application encounters high load and concurrent writes—then you will have to deal with nasty bugs that are difficult to reproduce locally or catch in tests. Read on for the comparison and benchmarks of advanced approaches that will make your application more robust and your data—consistent.