练习Practice
动手做Get your hands on it
练习跟着课文走 —— 每节课尾都有本课的练习。这一页是全部练习的总库，想集中刷题的时候来。 每个练习都写清了它来自哪一节，卡住了就回去看那一节。Practice follows the lessons — every lesson ends with the exercises for that lesson. This page is the whole library, for when you want to drill in one sitting. Each exercise names the lesson it came from, so you can go back when you stall.
0 / 148个做对过you got right
已筛到你正在学的《Federation 考试》。想看全部就点上面的「全部」。Filtered to Federation exam — the course you are on. Use “All” above to see everything.
练习Exercises
筛出 25 个练习（共 148 个） · 第 3 / 3 页。Showing 25 of 148 · page 3 / 3.来自From 两道书面题：延迟传播与生产配置The two written questions: how delay spreads, and production configuration · Federation 考试Federation exam
L1认出来Spot it为什么 User subgraph 慢会拖慢 Orders subgraphWhy a slow User subgraph slows the Orders subgraph down
客户端查 { user(id:"1") { name orders { id } } }。 Accounts subgraph 要 500ms，Orders subgraph 只要 10ms。 总延迟大约是多少，为什么？
A client asks for { user(id:"1") { name orders { id } } }. The Accounts subgraph takes 500ms, the Orders subgraph only 10ms. Roughly what is the total latency, and why?
先选一个选项Pick an option first