// https://jira.mongodb.org/browse/SERVER-4534
// Building an index in the forground on a field with a large array and few documents in
// the collection used to open too many files and crash the server.
t = db.huge_multikey_index;
t.drop();

function doit() {
    arr = [];
    for (var i = 0; i < 1000 * 1000; i++)
        arr.push(i);

    t.insert({a: arr});

    // t.ensureIndex({a:1}, {background:true}) // always worked

    t.ensureIndex({a: 1});  // used to fail server with out of fds error
}

doit();