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Practice · Scaling
Drill the scaling-bug shapes
One concrete scenario per card, four options to pick from. The wrong picks come with explanations — they're often the most valuable part. Pairs with the long-form Scaling series.
Card 1
Which single index helps this query most?
Card 2
Count the queries this view runs
Card 3
Failure mode of this cache under high traffic
Card 4
Why is page 50,000 so much slower?
Card 5
Why is the counter cache slowing down inserts?
Card 6
What's wrong with this counter increment?
Card 7
The signup is slow. What moves first?
Card 8
How many writes does this loop fire?
Want the theory? The full series of eight long-form Scaling lessons lives at Scaling. Each practice card here pairs with one of those.
← Back to Practice Practice · Scaling · 8 cards