Root user lack rights to use `tidb_mdl_view` about tidb HOT 1 CLOSED

The problem is that privilege check on system table mysql is failed:

When I check the value of tableInfo.View.Definer, it comes to be ''@'', which is not maintained by privilege manager. It will absolutely fail the check.

Since tidb_mdl_view is created during cluster initialization, no user is suitable to be View.Definer. So there is nothing wrong with ''@''.

#48728 changed the definition of tidb_mdl_view. Previously, we joined three system tables from information_schema:

FROM information_schema.ddl_jobs,
    information_schema.cluster_tidb_trx,
    information_schema.cluster_processlist

After #48728, they become

FROM mysql.tidb_ddl_job
    mysql.tidb_mdl_info,
    information_schema.cluster_tidb_trx

RequestVerificationWithUser() skips all checks related to information_schema:

When it is changed to mysql, the problem occurs.

from tidb.