* This patch removes the approach with DB polling needed to
determine if a "join" task is ready to run. Instead of running
a periodic scheduled job, each task completion now runs the
algorithm that finds all potentially affected join tasks
and schedules just one job (instead of a periodic job) to check
their readiness.
This solves a problem of system cascaded overloading in case of
having many very large joins (when a workflow has many joins with
many dependencies each). Previously, in such case Mistral created
too many periodic jobs that just didn't let the workflow progress
well, i.e. most CPU was used by scheduler to run those periodic
jobs that very rarely switched "join" tasks to the RUNNING state.
Change-Id: I5ebc44c7a3f95c868d653689dc5cea689c788cd0
Closes-Bug: #1799356
1a4c599a4d