Hi,

We encounter slowness with using the scrum plugin (https://redmine.ociotec.com/projects/redmine-plugin-scrum).
It happens when dragging issue in the backlog.
It seems that the slowness comes from the fact that there is no index on the parent_id field of the issues table :
Here we have more than 500.000 issues
and for example a simple @SELECT COUNT() FROM issues WHERE issues.parent_id = 520784@ *takes 0.28 seconds
The slow method is all_dependent_issues.

Aside from the use of this plugin, on issues with children, a request is made on the parent_id field, that takes a few hundreds of milli-seconds.
We have added an index on that field, that fixes the issue.

Can this index be added by default in the Redmine migrations ?

Thanks a lot