Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

upgrade-80.sql
drop index IndexBuildsOnJobsetIsCurrent;
drop index IndexBuildsOnJobIsCurrent;
drop index IndexBuildsOnJobset;
drop index IndexBuildsOnProject;
drop index IndexBuildsOnJobFinishedId;

alter table Builds
    drop column project,
    drop column jobset;