MDEV-7487 Semi-join optimization for single-table update/delete statementsbb-10.11-igor

This patch allows to use semi-join optimization at the top level of
single-table update and delete statements.
The problem of supporting such optimization became easy to resolve after
processing a single-table update/delete statement started using JOIN
structure. This allowed to use JOIN::prepare() not only for multi-table
updates/deletes but for single-table ones as well. This was done in the
patch for mdev-28883:
Re-design the upper level of handling UPDATE and DELETE statements.

Note that JOIN::prepare() detects all subqueries that can be considered
as candidates for semi-join optimization. The code added by this patch
looks for such candidates at the top level and if such candidates are found
in the processed single-table update/delete the statement is handled in
the same way as a multi-table update/delete.

    Approved by Oleksandr Byelkin <sanja@mariadb.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 72864b7e329..933b11e4a12 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -1214,7 +1214,7 @@ retry:
         }
       }
       else if (thd->lex->sql_command == SQLCOM_DELETE)
-      {
+     {
         Sql_cmd_delete *cmd= (Sql_cmd_delete *) (thd->lex->m_sql_cmd);
         if (cmd->is_multitable() || derived->derived->outer_select())
           materialize= false;