What is the recommended Start and End time and frequency to pull events?
When it comes to choosing the correct Start and End time of fetching events, there are a couple of options:
Recommended
Rolling Time Window (with Overlap).
Example
Start=Now-180 minutes,
End=Now
Frequency=Every 15 minutes
This option provides:
Best Latency: In this strategy as soon as an event such as Standard Rendezvous is in the Skylight system, it can be pulled it into your system
Most Complete Data: With AIS there are delays, by re-pulling for the same time period multiple times, you will not miss events that were delayed by AIS latency.
The disadvantage to this option is by pulling longer time periods, more data is being pulled. Also, there needs to be logic on your side to handle duplicate data.
Not Recommended
Discrete Time Window (no overlap)
Example
Start=Now-180 minutes,
End=Now-165 minutes,
Frequency=Every 15 minutes
Although this option is simpler from a data parsing perspective, we do not recommend it.
More Latency: This options requires choosing a period in the past to avoid missing data, thus increasing the latency which is bound by the start time-frequency.
Incomplete Data: Calling only once means any AIS data that is delayed will be missed and not picked up in a subsequent call. The closer the start time is to real time, the more missed data/events there will be.
What interval should be used to fetch events? (How far back should we go?)
The latency of Skylight events can effect the number of events that will be retrieved. In general we recommend pulling events