fix(rdb): fix load balancer removal not detected (#3301)

Author: jremy42

internal/services/rdb/helpers.go

@@ -106,3 +106,16 @@ func getIPConfigUpdate(d *schema.ResourceData, ipFieldName string) (ipamConfig *
 
 	return ipamConfig, staticConfig
 }
+
+// LoadBalancerDiffSuppressFunc suppresses diff when load_balancer is not set
+func LoadBalancerDiffSuppressFunc(k, oldValue, newValue string, d *schema.ResourceData) bool {
+	if !strings.HasPrefix(k, "load_balancer") {
+		return false
+	}
+
+	if _, exists := d.GetOk("load_balancer"); !exists {
+		return true
+	}
+
+	return false
+}

internal/services/rdb/instance.go

@@ -260,10 +260,12 @@ func ResourceInstance() *schema.Resource {
 				Description: "Certificate of the database instance",
 			},
 			"load_balancer": {
-				Type:        schema.TypeList,
-				Optional:    true,
-				Computed:    true,
-				Description: "Load balancer of the database instance",
+				Type:             schema.TypeList,
+				Optional:         true,
+				Computed:         true,
+				MaxItems:         1,
+				Description:      "Load balancer of the database instance",
+				DiffSuppressFunc: LoadBalancerDiffSuppressFunc,
 				Elem: &schema.Resource{
 					Schema: map[string]*schema.Schema{
 						// Computed