gistfile1.txt

> version()
2.4.4
> db.test.insert({Country:'UK'});
> db.test.insert({Country:'US'});
> db.test.ensureIndex({"Country":1});
> db.test.find({Country:/S/}).explain();
{
	"cursor" : "BtreeCursor Country_1 multi",
	"isMultiKey" : false,
	"n" : 1,
	"nscannedObjects" : 1,
	"nscanned" : 2,
	"nscannedObjectsAllPlans" : 1,
	"nscannedAllPlans" : 2,
	"scanAndOrder" : false,
	"indexOnly" : false,
	"nYields" : 0,
	"nChunkSkips" : 0,
	"millis" : 0,
	"indexBounds" : {
		"Country" : [
			[
				"",
				{
					
				}
			],
			[
				/S/,
				/S/
			]
		]
	},
	"server" : "air.local:27017"
}