MySQL backup and consistency of database and dump file

Hi Everyone,

We are trying to workaround failed backups due to
https://bugs.launchpad.net/ubuntu/+source/mysql-5.7/+bug/2003866 . We
used to use --single-transaction, but the option now requires RELOAD
or FLUSH_TABLES. We failed to enable the privileges for the mwuser.

MediaWiki's backup documentation is at
https://www.mediawiki.org/wiki/Manual:Backing_up_a_wiki . Here is the
command MediaWiki recommends:

    mysqldump -h hostname -u userid -p \
        --default-character-set=whatever dbname > backup.sql

But the article does not discuss how to ensure consistency for the
database and dump file. For MySQL, that should be --single-transaction
or --lock-tables. (If I am reading the MySQL documentation correctly).

My question is, what should we use to ensure consistency of the dump file?

--single-transaction or --lock-tables or something else?

Jeff