Add dag_run to the task_instance table or create new taskuuid column and use this to uniquely identify a task

[dimberman]

Apache Airflow version: None given

Ticket was created 21/Nov/16 18:35

Kubernetes version (if you are using kubernetes) (use kubectl version):

Environment:

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• OS (e.g. from /etc/os-release):
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  What happened:

We are planning to run around 40,000 tasks a day using airflow and some of them are critical to give quick feedback to developers.

Currently having execution date to uniquely identify tasks does not work for us since we mainly trigger dags (instead of running them on schedule) we collide with 1 sec granularity on several occasions. Having a task uuid or associating dag_run to task_instance table and using this for scheduling and updating status will help us here.

What you expected to happen:

How to reproduce it:

Anything else we need to know:

Moved here from https://issues.apache.org/jira/browse/AIRFLOW-642

[ashb]

Duplicate of #7967