Day 5 drills

Written on paper first. Today is about API design and pagination, so reason about rows read, retries, and endpoints, not stopwatch numbers.

D1 (page 500: rows read by offset vs keyset, and the ratio):

D2 (payment retry: without a key, with a key, what makes a good key):

D3 (four food-delivery endpoints: method, path, status code):

D4 (newest-first feed, 5 new posts then page 2: seen twice; 5 deleted: missed):

D5 (sync 10M rows, 20 per page at 50 ms each; then 200 per page; the tradeoff):