MDEV-16519 : mariabackup should fail if MDL could not be acquired with lock-ddl-per-table

There is a tiny chance for race condition during MDL acquisition.

If table is renamed just prior to
SELECT 1 FROM <table_name> LIMIT 0

then this query would  fail, yet mariabackup --backup does not handle
it as fatal error and continues, only to fail later during file copy.

The fix is to die on error, of MDL lock query fails.

2 files changed, 16 insertions, 0 deletions

diff --git a/mysql-test/suite/mariabackup/rename_during_mdl_lock.result b/mysql-test/suite/mariabackup/rename_during_mdl_lock.result
new file mode 100644
index 00000000000..982851438f2
--- /dev/null
+++ b/mysql-test/suite/mariabackup/rename_during_mdl_lock.result
@@ -0,0 +1,3 @@
+CREATE TABLE t1(i int) ENGINE INNODB;
+FOUND 1 /failed to execute query SELECT 1 FROM/ in backup.log
+DROP TABLE t2;
diff --git a/mysql-test/suite/mariabackup/rename_during_mdl_lock.test b/mysql-test/suite/mariabackup/rename_during_mdl_lock.test
new file mode 100644
index 00000000000..0a41f1dfe74
--- /dev/null
+++ b/mysql-test/suite/mariabackup/rename_during_mdl_lock.test
@@ -0,0 +1,13 @@
+--source include/have_debug.inc
+let $targetdir=$MYSQLTEST_VARDIR/backup;
+mkdir $targetdir;
+CREATE TABLE t1(i int) ENGINE INNODB;
+--error 1
+exec  $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf  --backup  --target-dir=$targetdir  --lock-ddl-per-table --dbug=+d,rename_during_mdl_lock_table 2>$targetdir/backup.log;
+
+let SEARCH_FILE=$targetdir/backup.log;
+let SEARCH_PATTERN=failed to execute query SELECT 1 FROM;
+source include/search_pattern_in_file.inc;
+
+DROP TABLE t2;
+rmdir $targetdir;