Bug#1024515: mariadb-10.6: FTBFS on s390x: test main.order_by_innodb failed with type 'ref'

Source: mariadb-10.6
Version: 1:10.6.11-1
Tags: ftbfs
User: [email protected]
Usertags: s390x
X-Debbugs-CC: [email protected]
Severity: serious
Justification: fails to build from source on official Debian architecture


After upload of mariadb-10.6 1:10.6.11-1 I noticed that s390x builds
at https://buildd.debian.org/status/package.php?p=mariadb-10.6 were
failing:

************************************************************************************
main.order_by_innodb 'innodb'            w2 [ fail ]
        Test ended at 2022-11-20 00:18:24

CURRENT_TEST: main.order_by_innodb
--- /<<PKGBUILDDIR>>/mysql-test/main/order_by_innodb.result 2022-11-03
10:20:33.000000000 +0000
+++ /<<PKGBUILDDIR>>/mysql-test/main/order_by_innodb.reject 2022-11-20
00:18:24.074583262 +0000
@@ -220,6 +220,6 @@
 id select_type table type possible_keys key key_len ref rows Extra
 1 PRIMARY t1 index NULL PRIMARY 4 NULL # Using index
 1 PRIMARY t2 eq_ref PRIMARY,id2 PRIMARY 4 func # Using where
-2 DEPENDENT SUBQUERY dd range id2,for_latest_sort for_latest_sort 6
NULL # Using where
+2 DEPENDENT SUBQUERY dd ref id2,for_latest_sort id2 4 test.t1.id #
Using where; Using filesort
 drop table t1,t2;
 # End of 10.2 tests
************************************************************************************

I restarted the build, and failure repeated, so this is not sporadic.

This is a regression as s390x builds used to work on MariaD 10.6.10-1:
https://buildd.debian.org/status/fetch.php?pkg=mariadb-10.6&arch=s390x&ver=1%3A10.6.10-1%2Bb1&stamp=1665890624&raw=0

Please help by providing info on this bug report or - preferably -
submit a MR to fix
this: https://salsa.debian.org/mariadb-team/mariadb-server/-/wikis/Contributing-to-MariaDB-packaging-in-Debian