Dmitry Shulga bab989ab38 MDEV-26145: Incorrect metadata is sent on running query with union in PS mode ...

Test cases like the following one produce different result sets if it's run
with and without th option --ps-protocol.

CREATE TABLE t1(a INT);
--enable_metadata
(SELECT MAX(a) FROM t1) UNION (SELECT MAX(a) FROM t1);
--disable_metadata
DROP TABLE t1;

Result sets differ in metadata for the query
  (SELECT MAX(a) FROM t1) UNION (SELECT MAX(a) FROM t1);

The reason for different content of query metadata is that for queries
with union the items being created on JOIN preparing phase is placed into
item_list from SELECT_LEX_UNIT whereas for queries without union item_list
from SELECT_LEX is used instead.

2021-07-19 19:25:11 +07:00

163 KiB

Raw Blame History

View Raw