zhongjiajie commented on a change in pull request #8259: [AIRFLOW-XXX] Optimize
airflow scheduler
URL: https://github.com/apache/airflow/pull/8259#discussion_r407320763
##########
File path: airflow/jobs.py
##########
@@ -1644,26 +1738,31 @@ def _execute_helper(self, processor_manager):
# If a task instance is up for retry but the corresponding DAG
run
# isn't running, mark the task instance as FAILED so we don't
try
# to re-run it.
- self._change_state_for_tis_without_dagrun(simple_dag_bag,
- [State.UP_FOR_RETRY],
- State.FAILED)
+ ret = self._change_state_for_tis_without_dagrun(simple_dag_bag,
+
[State.UP_FOR_RETRY],
+ State.FAILED)
+ if not ret:
+ continue
# If a task instance is scheduled or queued, but the
corresponding
# DAG run isn't running, set the state to NONE so we don't try
to
# re-run it.
- self._change_state_for_tis_without_dagrun(simple_dag_bag,
- [State.QUEUED,
- State.SCHEDULED],
- State.NONE)
-
+ ret = self._change_state_for_tis_without_dagrun(simple_dag_bag,
+ [State.QUEUED,
+
State.SCHEDULED],
+ State.NONE)
+ if not ret:
+ continue
self._execute_task_instances(simple_dag_bag,
(State.SCHEDULED,))
# Call heartbeats
self.log.info("Heartbeating the executor")
self.executor.heartbeat()
- # Process events from the executor
- self._process_executor_events(simple_dag_bag)
+ # Process all events from the executor
+ full_simple_dag_bag = SimpleDagBag(self.full_simple_dags.values())
+ self.executor_events =
self._process_executor_events(full_simple_dag_bag)
Review comment:
> > Your change is targeted at Airflow 1.9, is that correct? Plus, please
describe your change.
>
> **Background**: Our team has been using Airflow 1.9 for two years. We use
it as the scheduler of our deploy system, but when the number of dags we need
to schedule at the same time exceeds 300, the task scheduling delay of Dag is
no longer stable, sometimes More than 1 minute.
> So I made improvements and fixes to the 1.9 version of Airflow. The
detailed improvement information is as follows (same as the [update
log](https://github.com/apache/airflow/pull/8259/files/edc04002ea6605b529088dc4d58e8631bec47577#diff-bb7ee25332d5fdca3ead2f545d72b359))：
>
> 1. Added a feedback event mechanism to the scheduler to make the task
scheduling delay stable at 3s;
> 2. Solved the problem of db deadlock caused by worker and scheduler
updating task_instance at the same time (this will cause the scheduler to exit
abnormally);
> 3. In order to improve the availability of the scheduler, I used
distributed locks to add a hot standby function to the scheduler.
Hi, @buhuipao I know what you said, but pls take a look at Jarek said above.
> We want to encourage people to update to the latest released 1.10 version
rather than fix the old version.
User would use latest release instead of 1.9, so I think we should target to
master branch. And I check your UPDATING.md, maybe we should separate PR which
easy to review, WDYT
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