MDEV-13911 Support ORDER BY and LIMIT in multi-table update

mysql-test/r/multi_update.result

@@ -942,3 +942,30 @@ deallocate prepare stmt1;
 drop view v3,v2,v1;
 drop table t1,t2,t3;
 end of 5.5 tests
+create table t1 (c1 int, c3 int);
+insert t1(c3) values (1), (2), (3), (4), (5), (6), (7), (8);
+create table t2 select * from t1;
+update t1, t2 set t1.c1=t2.c3 where t1.c3=t2.c3 order by t1.c3 limit 3;
+select * from t1;
+c1	c3
+1	1
+2	2
+3	3
+NULL	4
+NULL	5
+NULL	6
+NULL	7
+NULL	8
+update t1 set c1=NULL;
+update t1, t2 set t1.c1=t2.c3 where t1.c3=t2.c3 order by t1.c3 desc limit 2;
+select * from t1;
+c1	c3
+NULL	1
+NULL	2
+NULL	3
+NULL	4
+NULL	5
+NULL	6
+7	7
+8	8
+drop table t1, t2;

mysql-test/t/multi_update.test

@@ -901,3 +901,17 @@ deallocate prepare stmt1;
 drop view v3,v2,v1;
 drop table t1,t2,t3;
 --echo end of 5.5 tests
+
+#
+# MDEV-13911 Support ORDER BY and LIMIT in multi-table update
+#
+
+create table t1 (c1 int, c3 int);
+insert t1(c3) values (1), (2), (3), (4), (5), (6), (7), (8);
+create table t2 select * from t1;
+update t1, t2 set t1.c1=t2.c3 where t1.c3=t2.c3 order by t1.c3 limit 3;
+select * from t1;
+update t1 set c1=NULL;
+update t1, t2 set t1.c1=t2.c3 where t1.c3=t2.c3 order by t1.c3 desc limit 2;
+select * from t1;
+drop table t1, t2;

sql/sql_parse.cc

@@ -4525,6 +4525,7 @@ end_with_restore_list:
     else
       res= 0;
 
+    unit->set_limit(select_lex);
     res= mysql_multi_update_prepare(thd);
 
 #ifdef HAVE_REPLICATION
@@ -9059,7 +9060,6 @@ Item * all_any_subquery_creator(THD *thd, Item *left_expr,
 
 bool multi_update_precheck(THD *thd, TABLE_LIST *tables)
 {
-  const char *msg= 0;
   TABLE_LIST *table;
   LEX *lex= thd->lex;
   SELECT_LEX *select_lex= &lex->select_lex;
@@ -9115,15 +9115,6 @@ bool multi_update_precheck(THD *thd, TABLE_LIST *tables)
     }
   }
 
-  if (select_lex->order_list.elements)
-    msg= "ORDER BY";
-  else if (select_lex->select_limit)
-    msg= "LIMIT";
-  if (msg)
-  {
-    my_error(ER_WRONG_USAGE, MYF(0), "UPDATE", msg);
-    DBUG_RETURN(TRUE);
-  }
   DBUG_RETURN(FALSE);
 }
 

sql/sql_select.cc

@@ -1988,7 +1988,8 @@ int JOIN::optimize_stage2()
       FORCE INDEX FOR ORDER BY can be used to prevent join buffering when
       sorting on the first table.
     */
-    if (!stable || !stable->force_index_order)
+    if (!stable || (!stable->force_index_order &&
+                    !map2table[stable->tablenr]->keep_current_rowid))
     {
       if (group_list)
         simple_group= 0;

sql/sql_update.cc

@@ -1595,10 +1595,9 @@ bool mysql_multi_update(THD *thd,
   List<Item> total_list;
 
   res= mysql_select(thd,
-                    table_list, select_lex->with_wild,
+                    table_list, select_lex->with_wild, total_list, conds,
-                    total_list,
+                    select_lex->order_list.elements, select_lex->order_list.first,
-                    conds, 0, (ORDER *) NULL, (ORDER *)NULL, (Item *) NULL,
+                    (ORDER *)NULL, (Item *) NULL, (ORDER *)NULL,
-                    (ORDER *)NULL,
                     options | SELECT_NO_JOIN_CACHE | SELECT_NO_UNLOCK |
                     OPTION_SETUP_TABLES_DONE,
                     *result, unit, select_lex);
@@ -1857,6 +1856,8 @@ static bool safe_update_on_fly(THD *thd, JOIN_TAB *join_tab,
   TABLE *table= join_tab->table;
   if (unique_table(thd, table_ref, all_tables, 0))
     return 0;
+  if (join_tab->join->order) // FIXME this is probably too strong
+    return 0;
   switch (join_tab->type) {
   case JT_SYSTEM:
   case JT_CONST:
@@ -1934,6 +1935,7 @@ multi_update::initialize_tables(JOIN *join)
       }
     }
     table->prepare_for_position();
+    join->map2table[table->tablenr]->keep_current_rowid= true;
 
     /*
       enable uncacheable flag if we update a view with check option
@@ -2001,6 +2003,7 @@ loop_end:
         that we need a position to be read first.
       */
       tbl->prepare_for_position();
+      join->map2table[tbl->tablenr]->keep_current_rowid= true;
 
       Field_string *field= new Field_string(tbl->file->ref_length, 0,
                                             &field_name,