Enhancing Upserts with Ecto and PostgreSQL

The article, written by Paweł Świątkowski, provides an in-depth look at improving upserts in Ecto and PostgreSQL. It begins by explaining the basic concept of upserts, where a database operation tries to insert a new record and updates an existing one if a constraint violation occurs (typically a primary key). The article then discusses common issues such as race conditions and how they can be solved using the 'on_conflict' option in Ecto's 'Repo.insert!' function. Świątkowski introduces a method to emit events based on whether a record was inserted or updated, utilizing PostgreSQL's internal 'xmax' system column to achieve this. The article concludes with code examples and testing scenarios to demonstrate the effectiveness of these improvements.