Hi, Sergey! On Mar 13, Sergey Vojtovich wrote:

revision-id: d953dc02d9a (mariadb-10.4.1-137-gd953dc02d9a) parent(s): 9496394002f author: Sergey Vojtovich <svoj@mariadb.org> committer: Sergey Vojtovich <svoj@mariadb.org> timestamp: 2019-02-07 20:04:38 +0400 message:

Fix inplace ALTER TABLE to not register tmp table

Do not register intermediate tables created by inplace ALTER TABLE in THD::temporary_tables.

For inplace ALTER TABLE moved .frm creation to create_table_for_inplace_alter(). For regular ALTER TABLE it is (and was redundantly) created by ha_create_table().

Removed open_in_engine argument of create_and_open_tmp_table() and open_temporary_table(): it became unused after this patch.

Part of MDEV-17805 - Remove InnoDB cache for temporary tables.

Looks ok code wise. But I don't see what are you gaining by this transformation. Regards, Sergei Chief Architect MariaDB and security@mariadb.org