120 cards
This deck walks you through the core ideas behind PostgreSQL indexing, starting from what an index actually is and building up to more nuanced topics like composite key ordering, index-only scans, and partial indexes. You'll get comfortable with the default B-tree access method, learn the practical SQL syntax for creating single-column, unique, and multi-column indexes, and explore how PostgreSQL decides whether an index can be used for a given query. By the end, you should have a clear mental model of when indexes help, when they don't, and what they cost.
It's a good fit for developers and database practitioners who want to move beyond writing queries that just work and start tuning them for performance. If you're preparing for a backend or database-focused interview, maintaining a production PostgreSQL database, or simply curious about how the query planner uses indexes under the hood, these cards will give you a solid working vocabulary. The questions mix conceptual understanding ("why does column order matter?") with concrete commands, so you can both explain the reasoning and produce the right SQL on the spot.
To get the most out of the deck, try to connect each card to a real table you work with, even if only in your head, and ask yourself whether the rule in question would change your index choices there. The material is cumulative, so spacing your review sessions over several days will help the trade-offs between read speed, write overhead, and storage size stick better than cramming. When you hit a card about syntax, actually type the command into a scratch database alongside the deck to reinforce the muscle memory.