The feed of latest orders
The feed of latest orders
The admin panel's main screen shows twenty fresh orders. To hand back twenty rows, the machine sorts a hundred and fifty thousand.
There is no filter here at all — only an order. An index can hand out an order ready-made: it is stored sorted.
Make sure no Sort node is left in the plan.
Speed this query up with an index
SELECT * FROM orders ORDER BY created_at LIMIT 20
Requisito da solução
Apenas CREATE/ALTER/DROP — não é preciso um SELECT no final.
What counts as solved
You may only change the schema: indexes and ANALYZE. The query stays as the task wrote it — no need to send it back.
- the plan has no Sort
- the plan has no Seq Scan on orders
- the query reads at most 12 8 KB pages
Grading runs on a larger dataset than the samples show — the answer has to hold at scale.
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