SQLite claims to be one of the most popular pieces of software in the world, being integrated into every major operating system and browser. It became the ultimate database for client side apps. In recent years, there's also been a growing interest in using SQLite on the backend. If you do this, you better keep in mind a major SQLite limitation: concurrent writes.
SQLite handles concurrent writes with a global write lock allowing only one writer at a time. If you have many concurrent write transactions, some will take a long time and some may even fail with the "database is locked" error. What I'd like to do in this post is to better understand how concurrent writes impact SQLite performance, how many are ok, and how we can improve it.