I think you can construct a request like:
Where you specify the
fromtime in Unix *milliseconds* based timestamp, as well as the toTime
The expand=default only has performance metrics for the various objects of the thing we are talking about - not the invidual samples the expand=history has.
For example, on the demo (sales) database, one of the nodes has
|description||"Latency - Read"|
You would want to use the "avg" latency for your use case.
I hope this helps. This is not my area of expertize, but most of the OCI folks have been travelling to Las Vegas over the last day or two - I am at 36k feet right now myself