Provide an easy way to list table currently in DISCARDED state.

Right now the best way I could come up with to check whether there might be a DISCARDed table/tablespace on a MariaDB server instance is building upon the fact that discarded tablespaces do not show up in INNODB_SYS_TABLESPACES:

SELECT T.TABLE_SCHEMA, T.TABLE_NAME

  FROM INFORMATION_SCHEMA.TABLES T

  LEFT OUTER JOIN INFORMATION_SCHEMA.INNODB_SYS_TABLESPACES I

    ON CONCAT(T.TABLE_SCHEMA,'/',T.TABLE_NAME) = I.NAME

 WHERE T.ENGINE='InnoDB'

   AND T.CREATE_OPTIONS NOT LIKE '%partitioned%'

   AND I.FILENAME IS NULL;

This obviously does not work for discarded partitions, and may also otherwise generate false positives.

A more direct and more reliable method to check for tables with discarded tablespaces would be appreciated.