問題文
An alarm fired and the console shows it as firing, yet the electronic mail address on the topic received nothing. What should be checked first?
選択肢
- Whether the metric has a dimension because a message is sent for each dimension and an empty dimension produces no message at all.
- Whether the alarm has a repeat interval because the first message of an alarm is suppressed until the repeat interval has passed once.
- Whether the retention period of the topic has expired because a topic keeps the messages for a fixed window and drops them once that window has closed for the alarm.
- Whether the subscription for that address was ever confirmed because a subscription stays pending until the owner of the address accepts it and pending subscriptions receive nothing.