do not include empty tags in hash

models/points.go

@@ -1021,6 +1021,10 @@ func (p *point) Tags() Tags {
 			i, key = scanTo(p.key, i, '=')
 			i, value = scanTagValue(p.key, i+1)
 
+			if len(value) == 0 {
+				continue
+			}
+
 			tags[string(unescapeTag(key))] = string(unescapeTag(value))
 
 			i += 1
@@ -1141,7 +1145,10 @@ func (t Tags) HashKey() []byte {
 	for k, v := range t {
 		ek := escapeTag([]byte(k))
 		ev := escapeTag([]byte(v))
-		escaped[string(ek)] = string(ev)
+
+		if len(string(ev)) > 0 {
+			escaped[string(ek)] = string(ev)
+		}
 	}
 
 	// Extract keys and determine final size.

models/points_test.go

@@ -605,6 +605,18 @@ func TestParsePointUnescape(t *testing.T) {
 			},
 			time.Unix(0, 0)))
 
+	// tag with no value
+	test(t, `cpu,regions=east value="1"`,
+		models.NewPoint("cpu",
+			models.Tags{
+				"regions": "east",
+				"foobar":  "",
+			},
+			models.Fields{
+				"value": "1",
+			},
+			time.Unix(0, 0)))
+
 	// commas in field values
 	test(t, `cpu,regions=east value="1,0"`,
 		models.NewPoint("cpu",