[{"collection":"collection","count":100,"content":{"name":{"type":"int","min":0,"max":5},"value":{"type":"int","min":0,"max":100}},"indexes":[{"name":"ix","key":{"name":1}}]}]

db.collection.aggregate([{"$setWindowFields":{"partitionBy":"$name","output":{"groupCnt":{"$sum":1}}}},{"$match":{"groupCnt":{"$gt":1}}}]).explain("executionStats")