MDEV-7487 Semi-join optimization for single-table UPDATE/DELETEsbb-10.7-mdev-7487

This is a preliminary patch.

1 files changed, 11 insertions, 1 deletions

diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index 0ed25c3913d..7c48f8eaded 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -2671,6 +2671,8 @@ int multi_update::do_updates()
     table = cur_table->table;
     if (table == table_to_update)
       continue;					// Already updated
+    if (table->file->pushed_rowid_filter)
+      table->file->disable_pushed_rowid_filter();
     org_updated= updated;
     tmp_table= tmp_tables[cur_table->shared];
     tmp_table->file->extra(HA_EXTRA_CACHE);	// Change to read cache
@@ -2865,7 +2867,8 @@ int multi_update::do_updates()
     check_opt_it.rewind();
     while (TABLE *tbl= check_opt_it++)
         tbl->file->ha_rnd_end();
-
+    if (table->file->save_pushed_rowid_filter)
+      table->file->enable_pushed_rowid_filter();
   }
   DBUG_RETURN(0);
 
@@ -2876,6 +2879,8 @@ err:
   }
 
 err2:
+  if (table->file->save_pushed_rowid_filter)
+    table->file->enable_pushed_rowid_filter();
   if (table->file->inited)
     (void) table->file->ha_rnd_end();
   if (tmp_table->file->inited)
@@ -3126,6 +3131,11 @@ bool Sql_cmd_update::prepare_inner(THD *thd)
       goto err;
     }
 
+    if (!multitable &&
+        select_lex->sj_subselects.elements &&
+        !select_lex->order_list.elements &&
+        select_lex->master_unit()->lim.get_select_limit() == HA_POS_ERROR)
+      multitable= true;
   }
 
   free_join= false;