問題文
An operations team runs an order API for an online store. During a busy sale they need to answer, at any moment, how many requests per second the service handles and what share of them fail. They also want the answer to stay cheap to store after months of traffic. Which property of metrics makes them the right signal for this need?
選択肢
- Metrics keep the full text of every request and response, letting the team recount exact totals afterwards whenever a new question comes up.
- Metrics attach a unique identifier to every request, so one request can be followed across all the store services it touched during the sale.
- Metrics are numeric values kept as time series, so storage grows with the series count and the sampling interval rather than with traffic volume.
- Metrics are stored without timestamps, so one recorded value can be reused for any point in time and the total volume never grows at all.