I believe none of the answers listed is 100% correct.
Seems that 'key requests' are 'Timeseries metrics' and therefor only limited by the amount of Cassandra diskspace available. So limitation lies within granularity and there the minimum interval is 1 -minute for the first 14 days and 5 minutes for 14-28 days.
So, I'd think the last option 14-28 days... is the 'best' answer, but it won't be 'single-request' granulatiry if more request happened within 5 minutes.
By default, detailed history of all requests is stored for 10 days. Longer-term historical data is maintained for requests that you manually identify as key requests. Trend lines for key requests are stored perpetually, however the granularity of long-term history is gradually reduced over time:
This is the correct answer. Here is the link to the documentation, with all the details about Data retention periods:
As you can see, the Requests and request attributes are stored in Dynatrace Saas for 35 days.
Sorry but I realize that Dynatrace exam test considers "14-28 days" answer as wrong
On the other hand , explicit reference to 35 days is not reflected on the dynatrace documentation
And to have a "clear view" (ironic mode) Dynatrace documentation reflects as Unlimited the data retention for key requests (https://www.dynatrace.com/support/help/how-to-use-dynatrace/data-privacy-and-security/data-privacy/d... 😞
Maybe dynatrace certification exams are wrong ?
I really appreciate your comments and references for clarifying!
As Hannah wrote in this topic earlier, requests and request attributes the stored for the same amount of time, whatever if it is a key request or not. So the correct answer is 35 days, as we can see in this documentation file:
In the question that you posted, there is a clear mention of the single-request granularity. The timeseries metrics are for the interval granularity (so the different kind of granularity than the question is asking about), as you can see here:
The single-request granularity, as Hannah already mentioned, is raw data. That is stored for the same amount of time whether it is a key request or not. The answer, in this case, is 35 days.
I hope that this clarifies everything!