Find checksum table SQL command returns NULL when wsrep_trx_fragment_size set. Kindly advise is it a bug and as expected.

Steps to reproduce:

1. 1. 1. install MariaDB and Galera RPM in redhat or centos as root

1. 1. 1. setup a simple one node Galera

rm -f /etc/my.cnf.d/galera.cnf

echo "[mysqld]" >> /etc/my.cnf.d/galera.cnf
echo "default_storage_engine=InnoDB" >> /etc/my.cnf.d/galera.cnf
echo "binlog_format=row" >> /etc/my.cnf.d/galera.cnf
echo "innodb_autoinc_lock_mode=2" >> /etc/my.cnf.d/galera.cnf
echo "" >> /etc/my.cnf.d/galera.cnf
echo "# Galera cluster configuration" >> /etc/my.cnf.d/galera.cnf
echo "wsrep_on=ON" >> /etc/my.cnf.d/galera.cnf
echo "wsrep_provider=/usr/lib64/galera-4/libgalera_smm.so" >> /etc/my.cnf.d/galera.cnf
echo "wsrep_cluster_address=\"gcomm://127.0.0.1\" " >> /etc/my.cnf.d/galera.cnf

systemctl set-environment _WSREP_NEW_CLUSTER='--wsrep-new-cluster'
systemctl start mariadb
systemctl unset-environment _WSREP_NEW_CLUSTER

mysql

create database testdb1 ;
create table t1 (c1 int primary key) ;
insert into t1 values (100) ;
commit ;

1. 1. 1. checksum table is working as-of now

checksum table testdb1.t1 ;

----------------------+

----------------------+

----------------------+
1 row in set (0.002 sec)

1. 1. 1. set wsrep_trx_fragment_size and login DB

set global wsrep_trx_fragment_size=10485760 ;

quit

mysql

1. 1. 1. checksum table return NULL now

checksum table testdb1.t1 ;

--------------------+

--------------------+

--------------------+
1 row in set, 1 warning (0.000 sec)

1. 1. 1. tried setting wsrep_trx_fragment_unit to bytes or rows or statements, all got the same result