Mysql select speed

I have a problem with a speed of mysql query. I have 2 select boxes with country and cities, on first select changes cities on the second, its provided by ajax:

$(document).ready(function()
{

$(".country").change(function()
{
var id=$(this).val(); 
var dataString = 'id='+ id;
function doAJAX(url) {

$.ajax
({
type: "POST",
url: url,

data: dataString,
cache: false,
success: function(html)
{
$(".city").html(html); 
}

});
}




doAJAX('search_ajax.php');
});
});

When is for example spain or russia where is so many cities, showing them took too much time, table cities:fips 2 varchar, city varchar 100, my select :

SELECT city from cities where fips='some value' //for example EN or any ..

I have on column fips index.

Can anobody help mi to speed this up? or is a better solution other than ajax to make live change of select's?? than开发者_C百科ks

Try creating an index on column fips.

I don't know if it could be marked as a solution, but I solved it by adding a loading gif when its requested from mysql, maybe it will help someone, the function changes to:

function doAJAX(url) {
    $(".city").hide(); // hide the select
    $("#Div1").show(); // show loading gif
    $("#Div1").html('<img src="images/loading2.gif"> Loading...'); 
    $.ajax({   
        type: "POST",
        url: url,    
        data: dataString,
        cache: false,
        success: function(html){
            $(".city").html(html);
            $(".city").show(); // on succes show select
            $("#Div1").hide(); // and hide the loading
        }
    });
}