mongodb/jstests/perf/find1.js

/**
 *  Performance tests for various finders
 */

var calls = 100;
var size = 500000;
var collection_name = "sort2";

function testSetup(dbConn) {
    var t = dbConn[collection_name];
    t.drop();

    for (var i = 0; i < size; i++) {
        t.save({num: i});
        if (i == 0)
            t.createIndex({num: 1});
    }
}

function resetQueryCache(db) {
    db[collection_name].createIndex({a: 1}, "dumbIndex");
    db[collection_name].dropIndex("dumbIndex");
}

function between(low, high, val, msg) {
    assert(low < val, msg);
    assert(val < high, msg);
}

/**
 *  Tests fetching a set of 10 objects in sorted order, comparing getting
 *  from  front of collection vs end, using $lt
 */
function testFindLTFrontBack(dbConn) {
    var results = {};
    var t = dbConn[collection_name];

    resetQueryCache(dbConn);
    results.oneInOrderLTFirst = Date.timeFunc(function() {
        assert(t.find({num: {$lt: 20}}).sort({num: 1}).limit(10).toArray().length == 10);
    }, calls);

    resetQueryCache(dbConn);
    results.oneInOrderLTLast = Date.timeFunc(function() {
        assert(t.find({num: {$lt: size - 20}}).sort({num: 1}).limit(10).toArray().length == 10);
    }, calls);

    between(0.9,
            1.1,
            results.oneInOrderLTFirst / results.oneInOrderLTLast,
            "first / last (" + results.oneInOrderLTFirst + " / " + results.oneInOrderLTLast +
                " ) = " + results.oneInOrderLTFirst / results.oneInOrderLTLast +
                " not in [0.9, 1.1]");
}

/**
 *  Tests fetching a set of 10 objects in sorted order, comparing getting
 *  from  front of collection vs end
 */
function testFindGTFrontBack(dbConn) {
    var results = {};
    var t = dbConn[collection_name];

    resetQueryCache(dbConn);
    results.oneInOrderGTFirst = Date.timeFunc(function() {
        assert(t.find({num: {$gt: 5}}).sort({num: 1}).limit(10).toArray().length == 10);
    }, calls);

    resetQueryCache(dbConn);
    results.oneInOrderGTLast = Date.timeFunc(function() {
        assert(t.find({num: {$gt: size - 20}}).sort({num: 1}).limit(10).toArray().length == 10);
    }, calls);

    between(0.25,
            4.0,
            results.oneInOrderGTFirst / results.oneInOrderGTLast,
            "first / last (" + results.oneInOrderGTFirst + " / " + results.oneInOrderGTLast +
                " ) = " + results.oneInOrderGTFirst / results.oneInOrderGTLast +
                " not in [0.25, 4.0]");
}

testSetup(db);

testFindLTFrontBack(db);
testFindGTFrontBack(db);