Merge 10.4 into 10.5

1 files changed, 6 insertions, 6 deletions

diff --git a/sql/opt_split.cc b/sql/opt_split.cc
index a6031f75a5b..3a086aef04c 100644
--- a/sql/opt_split.cc
+++ b/sql/opt_split.cc
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2017 MariaDB
+   Copyright (c) 2017, 2020, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -749,13 +749,13 @@ void JOIN::add_keyuses_for_splitting()
   if (allocate_dynamic(&keyuse, save_qep->keyuse.elements + added_keyuse_count))
     goto err;
 
-  memcpy(keyuse.buffer,
-         save_qep->keyuse.buffer,
-         (size_t) save_qep->keyuse.elements * keyuse.size_of_element);
-  keyuse.elements= save_qep->keyuse.elements;
+  idx= keyuse.elements= save_qep->keyuse.elements;
+  if (keyuse.elements)
+    memcpy(keyuse.buffer,
+           save_qep->keyuse.buffer,
+           (size_t) keyuse.elements * keyuse.size_of_element);
 
   keyuse_ext= &ext_keyuses_for_splitting->at(0);
-  idx= save_qep->keyuse.elements;
   for (i=0; i < added_keyuse_count; i++, keyuse_ext++, idx++)
   {
     set_dynamic(&keyuse, (KEYUSE *) keyuse_ext, idx);