Comment 5 for bug 1442910

So, you should do this:

use murano
delete from session;
delete from status;
delete from task;
delete from environment;

Or if u want to remove only one env, find out environment id u want to remove and do this:

delete from session WHERE environment_id='<env_id>';
select * from task WHERE environment_id='<env_id>'; <-- in exhaust find a task_id
delete from status WHERE task_id='<task_id>';
delete from task WHERE id='<task_id>';
delete from environment WHERE id='<env_id>';

Don't forget to remove heat-stack which belongs to this environment.