diff --git a/sql/field.cc b/sql/field.cc
index 155d8a4eb0d..1e2a711c956 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -7613,6 +7613,17 @@ int Field_varstring::save_field_metadata(uchar *metadata_ptr)
   return 2;
 }
 
+
+bool Field_varstring::memcpy_field_possible(const Field *from) const
+{
+  return (Field_str::memcpy_field_possible(from) &&
+          !compression_method() == !from->compression_method() &&
+          length_bytes == ((Field_varstring*) from)->length_bytes &&
+          (table->file && !(table->file->ha_table_flags() &
+                            HA_RECORD_MUST_BE_CLEAN_ON_WRITE)));
+}
+
+
 int Field_varstring::store(const char *from,size_t length,CHARSET_INFO *cs)
 {
   ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
diff --git a/sql/field.h b/sql/field.h
index db78efe0754..34d6684571b 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -3463,12 +3463,7 @@ public:
                                     length_bytes : 0);
   }
   Copy_func *get_copy_func(const Field *from) const;
-  bool memcpy_field_possible(const Field *from) const
-  {
-    return Field_str::memcpy_field_possible(from) &&
-           !compression_method() == !from->compression_method() &&
-           length_bytes == ((Field_varstring*) from)->length_bytes;
-  }
+  bool memcpy_field_possible(const Field *from) const;
   int  store(const char *to,size_t length,CHARSET_INFO *charset);
   using Field_str::store;
 #ifdef HAVE_valgrind_or_MSAN
diff --git a/sql/handler.h b/sql/handler.h
index af9fa068891..16fcab1e755 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -200,7 +200,8 @@ enum enum_alter_inplace_result {
 #define HA_HAS_NEW_CHECKSUM    (1ULL << 38)
 #define HA_CAN_VIRTUAL_COLUMNS (1ULL << 39)
 #define HA_MRR_CANT_SORT       (1ULL << 40)
-#define HA_RECORD_MUST_BE_CLEAN_ON_WRITE (1ULL << 41) /* unused */
+/* All of VARCHAR is stored, including bytes after real varchar data */
+#define HA_RECORD_MUST_BE_CLEAN_ON_WRITE (1ULL << 41)
 
 /*
   This storage engine supports condition pushdown
diff --git a/storage/maria/ha_maria.cc b/storage/maria/ha_maria.cc
index ec2a88de4df..c0163473f3a 100644
--- a/storage/maria/ha_maria.cc
+++ b/storage/maria/ha_maria.cc
@@ -1162,7 +1162,7 @@ int ha_maria::open(const char *name, int mode, uint test_if_locked)
     that all bytes in the row is properly reset.
   */
   if (file->s->data_file_type == STATIC_RECORD &&
-      (file->s->has_varchar_fields | file->s->has_null_fields))
+      (file->s->has_varchar_fields || file->s->has_null_fields))
     int_table_flags|= HA_RECORD_MUST_BE_CLEAN_ON_WRITE;
 
   for (i= 0; i < table->s->keys; i++)
diff --git a/storage/myisam/ha_myisam.cc b/storage/myisam/ha_myisam.cc
index fd2e8fd9425..0d9a2c6c18e 100644
--- a/storage/myisam/ha_myisam.cc
+++ b/storage/myisam/ha_myisam.cc
@@ -863,8 +863,9 @@ int ha_myisam::open(const char *name, int mode, uint test_if_locked)
     the full row to ensure we don't get any errors from valgrind and
     that all bytes in the row is properly reset.
   */
-  if ((file->s->options & HA_OPTION_PACK_RECORD) &&
-      (file->s->has_varchar_fields | file->s->has_null_fields))
+  if (!(file->s->options &
+        (HA_OPTION_PACK_RECORD | HA_OPTION_COMPRESS_RECORD)) &&
+      (file->s->has_varchar_fields || file->s->has_null_fields))
     int_table_flags|= HA_RECORD_MUST_BE_CLEAN_ON_WRITE;
 
   for (i= 0; i < table->s->keys; i++)