On your environments page, as of around Moodle 2.6 you might see a message like this:
unsupported_db_table_row_format if this test fails, it indicates a potential problem
Your database has tables using Antelope as the file format. You are recommended to convert the tables to the Barracuda file format. See the documentation Administration via command line for details of a tool for converting InnoDB tables to Barracuda.
If you are running MySQL/MariaDB, this message is advising you should move to the better InnoDB Barracuda format.
To perform the table upgrades, you use the Moodle cli (i.e. admin/cli) and run the following commands (prefix with sudo if relevant):
php admin/cli/mysql_compressed_rows.php -l
This lists tables that need compacting/compressing e.g.
mdl_data Compact (needs fixing) mdl_data_fields Compact (needs fixing) mdl_enrol_paypal Compact (needs fixing) mdl_lti Compact (needs fixing) mdl_user Compact (needs fixing) mdl_user_info_field Compact (needs fixing)
To fix, run the following. Note this can be database intensive so avoid running during high load periods or when there are a lot of active users on the site.
php admin/cli/mysql_compressed_rows.php -f mdl_data ... Compressed mdl_data_fields ... Compressed mdl_enrol_paypal ... Compressed mdl_lti ... Compressed mdl_user ... Compressed mdl_user_info_field ... Compressed
To confirm all is well, run the first info command again or check the admin/environment.php page again.