diff --git a/internal/server/scanner_test.go b/internal/server/scanner_test.go
new file mode 100644
index 00000000..fc021cb5
--- /dev/null
+++ b/internal/server/scanner_test.go
@@ -0,0 +1,52 @@
+package server
+
+import (
+	"math"
+	"math/rand"
+	"testing"
+	"time"
+
+	"github.com/tidwall/geojson"
+	"github.com/tidwall/geojson/geometry"
+)
+
+type testPointItem struct {
+	object geojson.Object
+	fields []float64
+}
+
+func PO(x, y float64) *geojson.Point {
+	return geojson.NewPoint(geometry.Point{X: x, Y: y})
+}
+
+
+func BenchmarkFieldMatch(t *testing.B) {
+	rand.Seed(time.Now().UnixNano())
+	items := make([]testPointItem, t.N)
+	for i := 0; i < t.N; i++ {
+		items[i] = testPointItem{
+			PO(rand.Float64()*360-180, rand.Float64()*180-90),
+			[]float64{rand.Float64()*9+1, math.Round(rand.Float64()*30) + 1},
+		}
+	}
+	sw := &scanWriter{
+		wheres: []whereT{
+			{"foo", false, 1, false, 3},
+			{"bar", false, 10, false, 30},
+		},
+		whereins: []whereinT{
+			{"foo", map[float64]struct{}{1: {}, 2: {}}},
+			{"bar", map[float64]struct{}{11: {}, 25: {}}},
+		},
+		fmap: map[string]int{"foo": 0, "bar": 1},
+		farr: []string{"bar", "foo"},
+	}
+	sw.fvals = make([]float64, len(sw.farr))
+	t.ResetTimer()
+	for i := 0; i < t.N; i++ {
+		// one call is super fast, measurements are not reliable, let's do 100
+		for ix := 0; ix < 100; ix++ {
+			sw.fieldMatch(items[i].fields, items[i].object)
+		}
+	}
+}