> db.f.drop()
true
> db.f.ensureIndex( {a:1,b:1} );
> db.f.find( {a:[1,2],b:1} ).sort( {b:1} ).explain()
{
	"cursor" : "BtreeCursor a_1_b_1 multi",
	"nscanned" : 0,
	"nscannedObjects" : 0,
	"n" : 0,
	"scanAndOrder" : true,
	"millis" : 4,
	"indexBounds" : [
		[
			{
				"a" : 1,
				"b" : 1
			},
			{
				"a" : 1,
				"b" : 1
			}
		],
		[
			{
				"a" : [
					1,
					2
				],
				"b" : 1
			},
			{
				"a" : [
					1,
					2
				],
				"b" : 1
			}
		]
	]
}
>