Marko Kattelus created AIRFLOW-7071:
---------------------------------------
Summary: LocalExecutor queuing behaviour
Key: AIRFLOW-7071
URL: https://issues.apache.org/jira/browse/AIRFLOW-7071
Project: Apache Airflow
Issue Type: Improvement
Components: scheduler
Affects Versions: 1.10.8
Reporter: Marko Kattelus
This is about question about possible improvement of queuing behaviour related
to LocalExecutor.
Here is example log from our test system.
{code}
14:22:45 scheduler.1 | [2020-02-20 14:22:45,015] \{base_executor.py:122} DEBUG
- 8 running task instances
14:22:45 scheduler.1 | [2020-02-20 14:22:45,015] \{base_executor.py:123} DEBUG
- 0 in queue
14:22:45 scheduler.1 | [2020-02-20 14:22:45,015] \{base_executor.py:124} DEBUG
- 0 open slots
14:22:45 scheduler.1 | [2020-02-20 14:22:45,016] \{base_executor.py:133} DEBUG
- Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync
method
14:22:47 scheduler.1 | [2020-02-20 14:22:47,200] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_17_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,200] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_16_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,201] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_15_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,202] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_14_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,202] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_13_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:47 scheduler.1 | [2020-02-20 14:22:47,203] \{base_executor.py:122} DEBUG
- 8 running task instances
14:22:47 scheduler.1 | [2020-02-20 14:22:47,203] \{base_executor.py:123} DEBUG
- 5 in queue
14:22:47 scheduler.1 | [2020-02-20 14:22:47,203] \{base_executor.py:124} DEBUG
- 0 open slots
14:22:47 scheduler.1 | [2020-02-20 14:22:47,203] \{base_executor.py:133} DEBUG
- Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync
method
14:22:47 scheduler.1 | [2020-02-20 14:22:47,204] \{base_executor.py:157} DEBUG
- Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_4_1',
datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC,
GMT, +00:00:00, STD]>), 1)
14:22:47 scheduler.1 | [2020-02-20 14:22:47,205] \{base_executor.py:157} DEBUG
- Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_19_1',
datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC,
GMT, +00:00:00, STD]>), 1)
14:22:49 scheduler.1 | [2020-02-20 14:22:49,128] \{base_executor.py:122} DEBUG
- 6 running task instances
14:22:49 scheduler.1 | [2020-02-20 14:22:49,128] \{base_executor.py:123} DEBUG
- 0 in queue
14:22:49 scheduler.1 | [2020-02-20 14:22:49,128] \{base_executor.py:124} DEBUG
- 2 open slots
14:22:49 scheduler.1 | [2020-02-20 14:22:49,128] \{base_executor.py:133} DEBUG
- Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync
method
14:22:49 scheduler.1 | [2020-02-20 14:22:49,129] \{base_executor.py:157} DEBUG
- Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_1_1',
datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC,
GMT, +00:00:00, STD]>), 1)
14:22:49 scheduler.1 | [2020-02-20 14:22:49,130] \{base_executor.py:157} DEBUG
- Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_3_1',
datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC,
GMT, +00:00:00, STD]>), 1)
14:22:49 scheduler.1 | [2020-02-20 14:22:49,131] \{base_executor.py:157} DEBUG
- Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_6_1',
datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC,
GMT, +00:00:00, STD]>), 1)
14:22:51 scheduler.1 | [2020-02-20 14:22:51,136] \{base_executor.py:122} DEBUG
- 3 running task instances
14:22:51 scheduler.1 | [2020-02-20 14:22:51,136] \{base_executor.py:123} DEBUG
- 0 in queue
14:22:51 scheduler.1 | [2020-02-20 14:22:51,136] \{base_executor.py:124} DEBUG
- 5 open slots
14:22:51 scheduler.1 | [2020-02-20 14:22:51,137] \{base_executor.py:133} DEBUG
- Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync
method
14:22:53 scheduler.1 | [2020-02-20 14:22:53,104] \{base_executor.py:122} DEBUG
- 3 running task instances
14:22:53 scheduler.1 | [2020-02-20 14:22:53,104] \{base_executor.py:123} DEBUG
- 0 in queue
14:22:53 scheduler.1 | [2020-02-20 14:22:53,105] \{base_executor.py:124} DEBUG
- 5 open slots
14:22:53 scheduler.1 | [2020-02-20 14:22:53,105] \{base_executor.py:133} DEBUG
- Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync
method
14:22:53 scheduler.1 | [2020-02-20 14:22:53,105] \{base_executor.py:157} DEBUG
- Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_5_1',
datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC,
GMT, +00:00:00, STD]>), 1)
14:22:55 scheduler.1 | [2020-02-20 14:22:55,111] \{base_executor.py:122} DEBUG
- 2 running task instances
14:22:55 scheduler.1 | [2020-02-20 14:22:55,111] \{base_executor.py:123} DEBUG
- 0 in queue
14:22:55 scheduler.1 | [2020-02-20 14:22:55,111] \{base_executor.py:124} DEBUG
- 6 open slots
14:22:55 scheduler.1 | [2020-02-20 14:22:55,111] \{base_executor.py:133} DEBUG
- Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync
method
14:22:55 scheduler.1 | [2020-02-20 14:22:55,112] \{base_executor.py:157} DEBUG
- Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_10_1',
datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC,
GMT, +00:00:00, STD]>), 1)
14:22:57 scheduler.1 | [2020-02-20 14:22:57,263] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'load_dag_test_6_entity_5_2_45', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,264] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_17_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,265] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_16_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,265] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_15_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,266] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_14_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,266] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_13_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,267] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_12_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,267] \{base_executor.py:58} INFO -
Adding to queue: ['airflow', 'run', 'DAG_TEST_6_5_20',
'dev.DAG_TEST_6_ENTITY_11_1', '2020-02-20T14:18:01.743479+00:00', '--local',
'--pool', 'default_pool', '-sd', '/airflow/dags/dag_DAG_TEST_6_5_20.py']
14:22:57 scheduler.1 | [2020-02-20 14:22:57,268] \{base_executor.py:122} DEBUG
- 1 running task instances
14:22:57 scheduler.1 | [2020-02-20 14:22:57,268] \{base_executor.py:123} DEBUG
- 8 in queue
14:22:57 scheduler.1 | [2020-02-20 14:22:57,268] \{base_executor.py:124} DEBUG
- 7 open slots
14:22:57 scheduler.1 | [[2020-02-20 14:22:57,2812020-02-20 14:22:57,281] \{]
{local_executor.py:base_executor.py:85} INFO133} DEBUG - - Calling the
QueuedLocalWorker<class 'airflow.executors.local_executor.LocalExecutor'>
running sync method
14:22:57 scheduler.1 | [2020-02-20 14:22:57,282] \{base_executor.py:157} DEBUG
- Changing state: ('DAG_TEST_6_5_20', 'dev.DAG_TEST_6_ENTITY_18_1',
datetime.datetime(2020, 2, 20, 14, 18, 1, 743479, tzinfo=<TimezoneInfo [UTC,
GMT, +00:00:00, STD]>), 1)
14:22:59 scheduler.1 | [2020-02-20 14:22:59,124] \{base_executor.py:122} DEBUG
- 7 running task instances
14:22:59 scheduler.1 | [2020-02-20 14:22:59,124] \{base_executor.py:123} DEBUG
- 0 in queue
14:22:59 scheduler.1 | [2020-02-20 14:22:59,124] \{base_executor.py:124} DEBUG
- 1 open slots
14:22:59 scheduler.1 | [2020-02-20 14:22:59,124] \{base_executor.py:133} DEBUG
- Calling the <class 'airflow.executors.local_executor.LocalExecutor'> sync
method
{code}
The issue is that implementation clears queue and ordering is even so that
LocalExecutor may been kept idle for no reason.
E.g.
# 8 running task instances 0 in queue 0 open slots
# 5 new tasks pushed to queue
# 2 tasks get ready
# 6 running task instances 0 in queue 2 slots open
# 3 tasks get ready
# 3 running task instances 0 in queue 5 open slots
# 1 tasks get ready
# 2 running task instances 0 in queue 6 open slots
# 8 new tasks pushed to queue
# 1 running task instances 8 in queue 7 open slots
# 1 task get ready
# 7 running task instances 0 in queue 1 slots open
So depending how often dag get rescheduled it might take long before we get
more tasks for LocalExecutor. Also it feels that now some other dags may get
scheduled just at the time when some tasks get ready and then kind of take
place of tasks queued before because those are always removed at then end of
every scheduler loop.
So would it be beneficial to keep queued tasks in local executor queue so that
LocalExecutor can start processing next task as soon as slot is available
instead of waiting until dag get scheduled next time.
Also as seen in 10,11,12 it seems that ordering of operations in LocalExecutor
heartbeating cause that actually after scheduler loop slots got available are
not filled all. Only those slots get used which are available before current
heartbeating or at least it looks like it.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
