To Index or To not Index. Leverage SQL indexing to hurry up your… | by Christopher Karg | Nov, 2024

Leverage SQL indexing to hurry up your queries. Be taught when to index, when to not, and the way indexing works beneath the hood.

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SQL indexing is a time period typically thrown round in knowledge circles — you’ll have heard phrases like “simply apply an index”. It is usually a query typically requested in interviews — “what steps can take to enhance question instances on desk X?”. It’s one thing that’s syntactically simple to implement however I’ve discovered not a lot consideration is paid to what truly occurs beneath the hood. On this article I purpose to just do that through the use of a relational MySQL Database (DB). I’ll cowl what an index is, methods to implement it, the way it works beneath the hood, together with some concerns of when to not use indexes. As with many applied sciences, even SQL indexes have their trade-offs.

In my examples I exploit a easy MySQL container from Docker. I don’t cowl how this works however be happy to succeed in out in case you have any questions. I’ll present the code I exploit to populate the DB on this article so that you can adapt on your personal use case and experiment your self.

I begin off with a high-level overview. The extra granular element is afterward within the article. As such, I hope I can present beneficial insights to a large readership of various technical inclinations. When you’re like me you’ll discover the visualisations in…