

[jsTest] ----
[jsTest] No indexes. Query: [ { "$match" : { "a.b" : null } } ]
[jsTest] ----

nReturned: 3
Plan skeleton: 
{
	"queryPlanner" : {
		"winningPlan" : {
			"queryPlan" : {
				"nodeType" : "Root",
				"child" : {
					"nodeType" : "Filter",
					"child" : {
						"nodeType" : "PhysicalScan"
					}
				}
			}
		}
	}
}


[jsTest] ----
[jsTest] Index on {  "a.b" : 1 }. Query: [ { "$match" : { "a.b" : null } } ]
[jsTest] ----

nReturned: 3
Plan skeleton: 
{
	"queryPlanner" : {
		"winningPlan" : {
			"queryPlan" : {
				"nodeType" : "Root",
				"child" : {
					"nodeType" : "NestedLoopJoin",
					"leftChild" : {
						"nodeType" : "IndexScan"
					},
					"rightChild" : {
						"nodeType" : "LimitSkip",
						"child" : {
							"nodeType" : "Seek"
						}
					}
				}
			}
		}
	}
}
