Bug#38499: flush tables and multitable table update with

           derived table cause crash

When a multi-UPDATE command fails to lock some table, and
subsequently succeeds, the tables need to be reopened if
they were altered. But the reopening procedure failed for
derived tables.

Extra cleanup has been added.


mysql-test/r/lock_multi.result:
  Added test case for bug #38499.
mysql-test/t/lock_multi.test:
  Added test case for bug #38499.
sql/sql_union.cc:
  Bug#38499: flush tables and multitable table update with
             derived table cause crash
  
  Obsolete assertion has been removed.
sql/sql_update.cc:
  Bug#38499: flush tables and multitable table update with
             derived table cause crash
  
  Extra cleanup for derived tables has been added:
  1) unit.cleanup(),
  2) unit->reinit_exec_mechanism().

1 files changed, 18 insertions, 0 deletions

diff --git a/mysql-test/r/lock_multi.result b/mysql-test/r/lock_multi.result
index d46aea24ac3..0430d560a7a 100644
--- a/mysql-test/r/lock_multi.result
+++ b/mysql-test/r/lock_multi.result
@@ -115,3 +115,21 @@ CREATE TABLE t3 SELECT * FROM t1;
 # normal mode
 # PS mode
 DROP TABLE t1, t2, t3;
+CREATE TABLE t1( a INT, b INT );
+INSERT INTO t1 VALUES (1, 1), (2, 2), (3, 3), (4, 4);
+# 1. test regular tables
+# 1.1. test altering of columns that multiupdate doesn't use
+# 1.1.1. normal mode
+# 1.1.2. PS mode
+# 1.2. test altering of columns that multiupdate uses
+# 1.2.1. normal mode
+# 1.2.2. PS mode
+ALTER TABLE t1 ADD COLUMN a INT;
+# 2. test UNIONs
+# 2.1. test altering of columns that multiupdate doesn't use
+# 2.1.1. normal mode
+# 2.1.2. PS mode
+# 2.2. test altering of columns that multiupdate uses
+# 2.2.1. normal mode
+# 2.2.2. PS mode
+DROP TABLE t1;