sort5.js

var t = db.sort5;
t.drop();

t.save({_id: 5, x: 1, y: {a: 5, b: 4}});
t.save({_id: 7, x: 2, y: {a: 7, b: 3}});
t.save({_id: 2, x: 3, y: {a: 2, b: 3}});
t.save({_id: 9, x: 4, y: {a: 9, b: 3}});

// test compound sorting

assert.eq( [4,2,3,1] , t.find().sort({"y.b": 1 , "y.a" : -1 }).map( function(z){ return z.x; } ) , "A no index" );
t.ensureIndex({"y.b": 1, "y.a": -1});
assert.eq( [4,2,3,1] , t.find().sort({"y.b": 1 , "y.a" : -1 }).map( function(z){ return z.x; } ) , "A index" );
assert(t.validate().valid, "A valid");

// test sorting on compound key involving _id

assert.eq( [4,2,3,1] , t.find().sort({"y.b": 1 , _id : -1 }).map( function(z){ return z.x; } ) , "B no index" );
t.ensureIndex({"y.b": 1, "_id": -1});
assert.eq( [4,2,3,1] , t.find().sort({"y.b": 1 , _id : -1 }).map( function(z){ return z.x; } ) , "B index" );
assert(t.validate().valid, "B valid");