Backup with MySQL locking tables and causing downtime

Summary

When running sudo /opt/gitlab/bin/gitlab-rake gitlab:backup:create SKIP=uploads,repositories,builds,artifacts,lfs,registry,pages with MySQL, tables are being lock causing a brief outage.

What is the current bug behavior?

Brief outage when running gitlab-rake gitlab:backup:create with MySQL.

What is the expected correct behavior?

There should not be an outage from locked tables.

Possible fixes

May be able to add --single-transaction in https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/backup/database.rb#L82-97 to prevent the creation of a table lock.

Customer ticket: https://gitlab.zendesk.com/agent/tickets/113945