Dont do empty "modify" calls for

Can be triggered every time auto-generated tags are removed

pkg/controller/database/rdsinstance.go

@@ -18,6 +18,7 @@ package database
 
 import (
 	"context"
+	"log"
 	"reflect"
 	"sort"
 
@@ -242,10 +243,18 @@ func (e *external) Update(ctx context.Context, mg resource.Managed) (managed.Ext
 	if err != nil {
 		return managed.ExternalUpdate{}, awsclient.Wrap(err, errDescribeFailed)
 	}
+
 	patch, err := rds.CreatePatch(&rsp.DBInstances[0], &cr.Spec.ForProvider)
 	if err != nil {
 		return managed.ExternalUpdate{}, errors.Wrap(err, errPatchCreationFailed)
 	}
+
+	upToDate, err := rds.IsUpToDate(ctx, e.kube, cr, rsp.DBInstances[0])
+	if len(patch.Tags) == 0 && upToDate && err == nil {
+		log.Println(cr.Name, "up to date after DescribeDBInstances")
+		return managed.ExternalUpdate{}, nil
+	}
+
 	modify := rds.GenerateModifyDBInstanceInput(meta.GetExternalName(cr), patch, cr.Spec.ForProvider.EnableCloudwatchLogsExports, rsp.DBInstances[0].EnabledCloudwatchLogsExports)
 	var conn managed.ConnectionDetails
 

pkg/controller/database/rdsinstance_test.go

@@ -863,11 +863,30 @@ func TestUpdate(t *testing.T) {
 						}, nil
 					},
 				},
+				cr: instance(withBackupRetentionPeriod(7)),
+			},
+			want: want{
+				cr:  instance(withBackupRetentionPeriod(7)),
+				err: awsclient.Wrap(errBoom, errModifyFailed),
+			},
+		},
+		"NotCallingModifyWithoutModifications": {
+			args: args{
+				rds: &fake.MockRDSClient{
+					MockModify: func(ctx context.Context, input *awsrds.ModifyDBInstanceInput, opts []func(*awsrds.Options)) (*awsrds.ModifyDBInstanceOutput, error) {
+						return nil, errors.New("should not be called")
+					},
+					MockDescribe: func(ctx context.Context, input *awsrds.DescribeDBInstancesInput, opts []func(*awsrds.Options)) (*awsrds.DescribeDBInstancesOutput, error) {
+						return &awsrds.DescribeDBInstancesOutput{
+							DBInstances: []awsrdstypes.DBInstance{{}},
+						}, nil
+					},
+				},
 				cr: instance(),
 			},
 			want: want{
 				cr:  instance(),
-				err: awsclient.Wrap(errBoom, errModifyFailed),
+				err: nil,
 			},
 		},
 		"FailedAddTags": {