I have a cloudwatch alarm configured :

Threshold : "GreaterThan 0" for 1 consecutive period,

Period : 1 minute,

Statistic : Sum

The alarm is configured on top of AWS SQS NumberOfMessagesSent. The queue was empty and no messages were being published to it. I sent a message manually. I could see the spike in metric but state of alarm was still OK. I am a bit confused why this alarm is not changing its state even though all the conditions to trigger this are met.