Execute GeoDjango query from multiple rows of data and read it using AJAX

I used AJAX to read the result of my query:

function e() {
    $.ajax({
        url: "tbl/",
        dataType: "json",
        beforeSend: function () {
            $("#info_tbl").show().text("Getting data from server...Please wait.").addClass("getme")
        },
        success: function (e) {
            function t(e) {
                return _.reduce(e, function (e, t) {
                    return e + parseFloat(t || 0)
                }, 0)
            }
            $("#info_tbl").text("Successfully Loaded!").fadeOut(1e3).removeClass("getme"), $("#myErrorWrapper").hide(), $("#table_wrapper").show();
            var a = _.chain(e).flatten().groupBy("brgy_locat", "municipali").map(function (e, r) {
                return {
                    municipality: _(e).chain().pluck("municipali").first(),
                    brgy: r,
                    low: t(_(e).chain().pluck("countlow").value()),
                    medium: t(_(e).chain().pluck("countmedium").value()),
                    high: t(_(e).chain().pluck("counthigh").value())
                }
            }).value();
            r.fnClearTable();
            for (var o = 0; o < a.length; o++) r.fnAddData([a[o].municipality, a[o].brgy, a[o].low || 0, a[o].medium || 0, a[o].high || 0])
        },
        error: function () {
            e(), $("#myErrorWrapper").show()
        }
    })
}

Is there any way to make it more efficient?

I am using PostgreSQL with PostGIS plugin. The data that I've been trying to query from the table consists of:

• 28k+ rows (multipolygon field and its attributes;varchar,int) - FloodHazard
• 2,500+ rows (multipolygon field and its attributes;varchar,int) - PolyStructures

That's why it takes a minute or more to show the result.

This is my function or query to identify if the building is affected by the flood hazard:

def floodhazard_tbl(request):
    if request.method == "GET":
        reference_high = FloodHazard.objects.filter(hazard='High')
        reference_medium = FloodHazard.objects.filter(hazard='Medium')
        reference_low = FloodHazard.objects.filter(hazard='Low')

        #get all ids based on filter
        ids_high = reference_high.values_list('id', flat=True)
        ids_medium = reference_medium.values_list('id', flat=True)
        ids_low = reference_low.values_list('id', flat=True)

        # create a list
        to_json = []

        # this code is results a messy JSON data that need underscore.js to manipulate
        # in order for us to use datatables
        for myid in ids_high:
            getgeom = FloodHazard.objects.get(id=myid).geom
            response_high = list(PolyStructures.objects.filter(geom__within=getgeom).values(
                'brgy_locat', 'municipali').annotate(counthigh=Count('brgy_locat')))
            to_json.append(response_high)

        for myid in ids_medium:
            getgeom = FloodHazard.objects.get(id=myid).geom
            response_medium = list(PolyStructures.objects.filter(geom__within=getgeom).values(
                'brgy_locat', 'municipali').annotate(countmedium=Count('brgy_locat')))
            to_json.append(response_medium)

        for myid in ids_low:
            getgeom = FloodHazard.objects.get(id=myid).geom
            response_low = list(PolyStructures.objects.filter(geom__within=getgeom).values(
                'brgy_locat', 'municipali').annotate(countlow=Count('brgy_locat')))
            to_json.append(response_low)


        return HttpResponse(list(json.dumps(to_json)), content_type='application/json')

It returns JSON data which is reconstructed using underscore.js and shows it using datatables.