[aodh]how the evaluation process works

Hello, I would like to understand how the evaluation process works. For example, I have this rule: openstack alarm create --name memory_use_test \ --type gnocchi_resources_threshold \ --metric memory.usage \ --threshold 102 \ --comparison-operator gt \ --aggregation-method mean \ --granularity 60 \ --evaluation-periods 3 \ --resource-id dca36039-c603-422c-8366-f6ba4e9539c3 \ --resource-type instance Does this mean that when the alarm-evaluator service is running per a period, it will check the last 3 data points, each aggregated over 60 seconds? Thank you. Regards. Nguyen Huu Khoi