With find, you can use explain (‘execution States’) to view query analysis, but aggregate used no explain query analysis, and you can’t see whether it uses indexes or sorts these problems in memory. …
You might as well read more official documents.
The options document can contain the following fields and values:explain,allowDiskUse,etc.
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MongoDB Online Lecture Series 19- MongoDB 10 Steps to Build a Single View
On April 19, please stamp: >—<