diff --git a/ChangeLog b/ChangeLog
index 91cdc8b7..23798fa9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,7 @@
 - redo im_draw_circle(), im_draw_flood(), im_draw_line(), im_draw_mask() as 
   classes
 - better rounding in vips_flatten()
+- VipsStatistic operations are sequential
 
 22/1/14 started 7.38.3
 - undeprecate VIPS_MASK_IDEAL_HIGHPASS and friends, ruby-vips was using them,
diff --git a/libvips.supp b/libvips.supp
index c3b3e74c..1e6c6ab1 100644
--- a/libvips.supp
+++ b/libvips.supp
@@ -373,6 +373,13 @@
    fun:rb_file_expand_path
 }
 
+{
+   ruby5
+   Memcheck:Value8
+   ...
+   fun:rb_enc_str_new
+}
+
 
 
 
diff --git a/libvips/arithmetic/statistic.c b/libvips/arithmetic/statistic.c
index e4553c5f..2c3df8fa 100644
--- a/libvips/arithmetic/statistic.c
+++ b/libvips/arithmetic/statistic.c
@@ -151,6 +151,7 @@ vips_statistic_class_init( VipsStatisticClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	gobject_class->set_property = vips_object_set_property;
 	gobject_class->get_property = vips_object_get_property;
@@ -159,6 +160,8 @@ vips_statistic_class_init( VipsStatisticClass *class )
 	vobject_class->description = _( "VIPS statistic operations" );
 	vobject_class->build = vips_statistic_build;
 
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL_UNBUFFERED;
+
 	VIPS_ARG_IMAGE( class, "in", 0, 
 		_( "Input" ), 
 		_( "Input image" ),