Reading from information_schema.PARAMETERS table in MariaDB is slower than MySQL by a factor of 20x in the best of cases, and deteriorates linearly in MariaDB once the number of reading threads exceeds the number of available cores, whereas in MySQL the deterioration remains more-or-less flat.
The following table shows relative performance running mysqlslap against the dataset provided in the attached sql file cs0401486-test.sql with this series of commands
Tests conducted in CentOS 7 machines with 1G RAM and approx. 800 real IOPS with one and four Intel i7-9750H cores @ 2.592GHz, average times reported:
Timings all on MariaDB 10.6.7. Confirmed on 10.6.8, 10.7.4, and 10.8.3 in Rocky Linux.