Understanding Query Components

Now that you understand what factors break your queries, it’s time to understand their components – tasks inside of them. Here we come back to something I’ve mentioned dozens of times throughout this book already – queries are tasks composed of other tasks. To ensure these tasks will execute successfully, we have to understand their components. Sounds simple enough, but if it were that simple, we would have way fewer people complaining about query performance, right? That’s why understanding query components is so crucial – a proper understanding of query internals can make or break your database instances.