Bug #26186:

When handling DELETE ... FROM if there is no
condition it is internally transformed to 
TRUNCATE for more efficient execution by the
storage handler.
The check for validity of the optional ORDER BY 
clause is done after the check for the above 
optimization and will not be performed if the
optimization can be applied.
Moved the validity check for ORDER BY before 
the optimization so it performed regardless of
the optimization.


mysql-test/r/delete.result:
  Bug #26186: test case
mysql-test/t/delete.test:
  Bug #26186: test case
sql/sql_delete.cc:
  Bug #26186: do validity check of the ORDER BY
  before deciding to skip it.

1 files changed, 21 insertions, 16 deletions

diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc
index 749ee04493b..e4b013ef088 100644
--- a/sql/sql_delete.cc
+++ b/sql/sql_delete.cc
@@ -60,6 +60,27 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
   if (mysql_prepare_delete(thd, table_list, &conds))
     DBUG_RETURN(TRUE);
 
+  /* check ORDER BY even if it can be ignored */
+  if (order && order->elements)
+  {
+    TABLE_LIST   tables;
+    List<Item>   fields;
+    List<Item>   all_fields;
+
+    bzero((char*) &tables,sizeof(tables));
+    tables.table = table;
+    tables.alias = table_list->alias;
+
+      if (select_lex->setup_ref_array(thd, order->elements) ||
+	  setup_order(thd, select_lex->ref_pointer_array, &tables,
+                    fields, all_fields, (ORDER*) order->first))
+    {
+      delete select;
+      free_underlaid_joins(thd, &thd->lex->select_lex);
+      DBUG_RETURN(TRUE);
+    }
+  }
+
   const_cond= (!conds || conds->const_item());
   safe_update=test(thd->options & OPTION_SAFE_UPDATES);
   if (safe_update && const_cond)
@@ -148,23 +169,7 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
   {
     uint         length= 0;
     SORT_FIELD  *sortorder;
-    TABLE_LIST   tables;
-    List<Item>   fields;
-    List<Item>   all_fields;
     ha_rows examined_rows;
-
-    bzero((char*) &tables,sizeof(tables));
-    tables.table = table;
-    tables.alias = table_list->alias;
-
-      if (select_lex->setup_ref_array(thd, order->elements) ||
-	  setup_order(thd, select_lex->ref_pointer_array, &tables,
-                    fields, all_fields, (ORDER*) order->first))
-    {
-      delete select;
-      free_underlaid_joins(thd, &thd->lex->select_lex);
-      DBUG_RETURN(TRUE);
-    }
     
     if ((!select || table->quick_keys.is_clear_all()) && limit != HA_POS_ERROR)
       usable_index= get_index_for_order(table, (ORDER*)(order->first), limit);