|-- A: map (nullable = true)
|    |-- key: string
|    |-- value: array (valueContainsNull = true)
|    |    |-- element: struct (containsNull = true)
|    |    |    |-- uid: string (nullable = true)
|    |    |    |-- price: double (nullable = true)
|    |    |    |-- type: string (nullable = true)
|-- keyindex: string (nullable = true)

{"A":{
 "innerkey_1":[{"uid":"1","price":0.01,"recordtype":"STAT"},
               {"uid":"6","price":4.3,"recordtype":"DYN"}],
 "innerkey_2":[{"uid":"2","price":2.01,"recordtype":"DYN"},
               {"uid":"4","price":6.1,"recordtype":"DYN"}]},
 "innerkey_2"}

val schema = (new StructType().add("mainkey", MapType(StringType, new ArrayType(new StructType().add("uid",StringType).add("price",DoubleType).add("recordtype",StringType), true))).add("keyindex",StringType))

[{"uid":"2","price":2.01,"recordtype":"DYN"},
 {"uid":"4","price":6.1,"recordtype":"DYN"}]