The Metrics Tracking Interval
API Gateway tracks performance metrics by intervals. Interval is a period of time you set in API Gateway, during which metrics are collected for reporting to CentraSite. You set the interval in the Publish Interval field on the API Gateway > Administration > Destinations > CentraSite Events page page in the Integration Server Administrator.
API Gateway only tracks metrics for the current interval. At the end of the interval, API Gateway aggregates the metrics and reports them to CentraSite. Once the metrics are reported, API Gateway resets its counters for the new interval. API Gateway does not calculate and aggregate metrics across intervals. If API Gateway is shut down or the virtual service is undeployed before the current interval expires, the performance data is discarded.
Note:
To avoid the need for API Gateway to store metrics during periods of inactivity, API Gateway stores only first and last zero value metrics that occurs during an interval, and discards the remaining consecutive zero value metrics. Doing this reduces the storage space consumed by the metrics, and speeds the queries you perform in the dashboard. Skipping the in-between zero metrics does not affect in the performance graphs shown in the dashboard.