using mysqldump while doing a backup gives the following error:

mysqldump: Got error: 1356: "View 'sys.host_summary' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them" when using LOCK TABLES

What can I do to fix that?

  • Where did you get the sys schema from? Did you install it from here? Or maybe you migrated from MySQL to MariaDB, and the sys schema came along somehow?
    – dbdemon
    Mar 10, 2019 at 9:13
  • Yes, I migrated from MySQL to MariaDB some days ago..
    – JHnet
    Mar 10, 2019 at 12:34
  • Probably you need to run mysql_upgrade.
    – Rick James
    Mar 14, 2019 at 1:54

1 Answer 1


The sys schema is not bundled with 10.3, but seems to be planned for 10.5. If you don't use/need it, you can safely remove it: DROP DATABASE sys;. If you do need it, you need to try resolving the issue outlined in the error message. For a start you can do SHOW CREATE VIEW sys.host_summary; to see which tables, views and functions it's referencing, as well as the definer/invoker.

  • 2
    I don't think I need it, it was just there, because I migrated from Mysql to MariaDB. So its safe to DROP DATABASE sys;?
    – JHnet
    Mar 10, 2019 at 12:36
  • 1
    @JHnet - yes, that's right, you can safely drop it like that.
    – dbdemon
    Mar 10, 2019 at 12:38
  • drop database sys --> Works for me; thank you Mar 24 at 10:55

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