Optimization on delete by removing ForceNew

internal/services/sql/sql_managed_instance_resource.go

@@ -1,6 +1,7 @@
 package sql
 
 import (
+	"context"
 	"fmt"
 	"log"
 	"strings"
@@ -166,11 +167,15 @@ func resourceArmSqlMiServer() *schema.Resource {
 				Type:         schema.TypeString,
 				Optional:     true,
 				ValidateFunc: azure.ValidateResourceID,
-				ForceNew:     true,
 			},
 
 			"tags": tags.Schema(),
 		},
+
+		CustomizeDiff: pluginsdk.ForceNewIfChange("dns_zone_partner_id", func(ctx context.Context, old, new, _ interface{}) bool {
+			// dns_zone_partner_id can only be set on init
+			return old.(string) == "" && new.(string) != ""
+		}),
 	}
 }
 

internal/services/sql/sql_managed_instance_resource_test.go

@@ -108,6 +108,14 @@ func TestAccAzureRMSqlMiServer_dnsZonePartner(t *testing.T) {
 			),
 		},
 		data.ImportStep("administrator_login_password", "dns_zone_partner_id"),
+		{
+			// DNS Zone Partner empty makes delete faster as MI can be destroyed simultaniously
+			Config: r.emptyDnsZonePartner(data),
+			Check: resource.ComposeTestCheckFunc(
+				check.That(data.ResourceName).ExistsInAzure(r),
+			),
+		},
+		data.ImportStep("administrator_login_password"),
 	})
 }
 
@@ -280,6 +288,37 @@ resource "azurerm_sql_managed_instance" "test1" {
 `, r.basic(data), r.templateSecondary(data), data.RandomInteger)
 }
 
+func (r SqlManagedInstanceResource) emptyDnsZonePartner(data acceptance.TestData) string {
+	return fmt.Sprintf(`
+%s
+
+%s
+
+resource "azurerm_sql_managed_instance" "test1" {
+  name                         = "acctestsqlserver2%d"
+  resource_group_name          = azurerm_resource_group.test1.name
+  location                     = azurerm_resource_group.test1.location
+  administrator_login          = "mradministrator"
+  administrator_login_password = "thisIsDog11"
+  license_type                 = "BasePrice"
+  subnet_id                    = azurerm_subnet.test1.id
+  sku_name                     = "GP_Gen5"
+  vcores                       = 4
+  storage_size_in_gb           = 32
+
+  depends_on = [
+    azurerm_subnet_network_security_group_association.test1,
+    azurerm_subnet_route_table_association.test1,
+  ]
+
+  tags = {
+    environment = "prod"
+    database    = "test"
+  }
+}
+`, r.basic(data), r.templateSecondary(data), data.RandomInteger)
+}
+
 func (SqlManagedInstanceResource) template(data acceptance.TestData) string {
 	return fmt.Sprintf(`
 resource "azurerm_resource_group" "test" {

website/docs/r/sql_managed_instance.html.markdown

@@ -235,7 +235,7 @@ The following arguments are supported:
 
 * `timezone_id` - (Optional) The TimeZone ID that the SQL Managed Instance will be operating in. Default value is `UTC`. Changing this forces a new resource to be created.
 
-* `dns_zone_partner_id` - (Optional) The ID of the Managed Instance which will share the DNS zone. This is a prerequisite for creating a failover group, although creation of a failover group is not yet possible in `azurerm`. Changing this forces a new resource to be created.
+* `dns_zone_partner_id` - (Optional) The ID of the Managed Instance which will share the DNS zone. This is a prerequisite for creating a failover group, although creation of a failover group is not yet possible in `azurerm`. Setting this after creation forces a new resource to be created.
 
 * `tags` - (Optional) A mapping of tags to assign to the resource.