[jira] [Commented] (AIRFLOW-246) dag_stats endpoint has a terrible query
[ https://issues.apache.org/jira/browse/AIRFLOW-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15358482#comment-15358482 ] Kengo Seki commented on AIRFLOW-246: Thanks ;) I'm going to file a new issue as a follow-up and fix query on that. > dag_stats endpoint has a terrible query > --- > > Key: AIRFLOW-246 > URL: https://issues.apache.org/jira/browse/AIRFLOW-246 > Project: Apache Airflow > Issue Type: Bug > Components: webserver >Affects Versions: Airflow 1.7.1 > Environment: MySQL Backend through sqlalchemy >Reporter: Neil Hanlon >Assignee: Kengo Seki > Fix For: Airflow 1.8 > > > Hitting this endpoint creates a series of queries on the database which take > over 20 seconds to run, causing the page to not load for that entire time. > Luckily the main page (which includes this under "Recent Statuses") loads > this synchronously, but still... waiting almost half a minute (at times more) > to see the statuses for dags is really not fun. > We have less than a million rows in the task_instance table--so it's not even > a problem with that. > Here's a query profile for the query: > https://gist.github.com/NeilHanlon/613f12724e802bc51c23fca7d46d28bf > We've done some optimizations on the database, but to no avail. > The query: > {code:sql} > SELECT task_instance.dag_id AS task_instance_dag_id, task_instance.state AS > task_instance_state, count(task_instance.task_id) AS count_1 FROM > task_instance LEFT OUTER JOIN (SELECT dag_run.dag_id AS dag_id, > dag_run.execution_date AS execution_date FROM dag_run WHERE dag_run.state = > 'running') AS running_dag_run ON running_dag_run.dag_id = > task_instance.dag_id AND running_dag_run.execution_date = > task_instance.execution_date LEFT OUTER JOIN (SELECT dag_run.dag_id AS > dag_id, max(dag_run.execution_date) AS execution_date FROM dag_run GROUP BY > dag_run.dag_id) AS last_dag_run ON last_dag_run.dag_id = task_instance.dag_id > AND last_dag_run.execution_date = task_instance.execution_date WHERE > task_instance.task_id IN ... AND (running_dag_run.dag_id IS NOT NULL OR > last_dag_run.dag_id IS NOT NULL) GROUP BY task_instance.dag_id, > task_instance.state; > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (AIRFLOW-246) dag_stats endpoint has a terrible query
[ https://issues.apache.org/jira/browse/AIRFLOW-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15358077#comment-15358077 ] Chris Riccomini commented on AIRFLOW-246: - I have no strong preference. Either JIRA or UPDATING.md or fixing query is fine with me. :) [~sekikn], since I think you'll end up doing the work--your call. > dag_stats endpoint has a terrible query > --- > > Key: AIRFLOW-246 > URL: https://issues.apache.org/jira/browse/AIRFLOW-246 > Project: Apache Airflow > Issue Type: Bug > Components: webserver >Affects Versions: Airflow 1.7.1 > Environment: MySQL Backend through sqlalchemy >Reporter: Neil Hanlon >Assignee: Kengo Seki > Fix For: Airflow 1.8 > > > Hitting this endpoint creates a series of queries on the database which take > over 20 seconds to run, causing the page to not load for that entire time. > Luckily the main page (which includes this under "Recent Statuses") loads > this synchronously, but still... waiting almost half a minute (at times more) > to see the statuses for dags is really not fun. > We have less than a million rows in the task_instance table--so it's not even > a problem with that. > Here's a query profile for the query: > https://gist.github.com/NeilHanlon/613f12724e802bc51c23fca7d46d28bf > We've done some optimizations on the database, but to no avail. > The query: > {code:sql} > SELECT task_instance.dag_id AS task_instance_dag_id, task_instance.state AS > task_instance_state, count(task_instance.task_id) AS count_1 FROM > task_instance LEFT OUTER JOIN (SELECT dag_run.dag_id AS dag_id, > dag_run.execution_date AS execution_date FROM dag_run WHERE dag_run.state = > 'running') AS running_dag_run ON running_dag_run.dag_id = > task_instance.dag_id AND running_dag_run.execution_date = > task_instance.execution_date LEFT OUTER JOIN (SELECT dag_run.dag_id AS > dag_id, max(dag_run.execution_date) AS execution_date FROM dag_run GROUP BY > dag_run.dag_id) AS last_dag_run ON last_dag_run.dag_id = task_instance.dag_id > AND last_dag_run.execution_date = task_instance.execution_date WHERE > task_instance.task_id IN ... AND (running_dag_run.dag_id IS NOT NULL OR > last_dag_run.dag_id IS NOT NULL) GROUP BY task_instance.dag_id, > task_instance.state; > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (AIRFLOW-246) dag_stats endpoint has a terrible query
[ https://issues.apache.org/jira/browse/AIRFLOW-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15358041#comment-15358041 ] Kengo Seki commented on AIRFLOW-246: bq. it delivers different results than before, as it double counts the TI belonging to the last DAG run if it is still running? Indeed. I totally missed that. Thanks for pointing out! bq. please open a JIRA about updating UPDATES.md. As another option, adding {{AND (state IS NULL OR state <> 'running')}} to the WHERE clause in the second subquery will fix this. > dag_stats endpoint has a terrible query > --- > > Key: AIRFLOW-246 > URL: https://issues.apache.org/jira/browse/AIRFLOW-246 > Project: Apache Airflow > Issue Type: Bug > Components: webserver >Affects Versions: Airflow 1.7.1 > Environment: MySQL Backend through sqlalchemy >Reporter: Neil Hanlon >Assignee: Kengo Seki > Fix For: Airflow 1.8 > > > Hitting this endpoint creates a series of queries on the database which take > over 20 seconds to run, causing the page to not load for that entire time. > Luckily the main page (which includes this under "Recent Statuses") loads > this synchronously, but still... waiting almost half a minute (at times more) > to see the statuses for dags is really not fun. > We have less than a million rows in the task_instance table--so it's not even > a problem with that. > Here's a query profile for the query: > https://gist.github.com/NeilHanlon/613f12724e802bc51c23fca7d46d28bf > We've done some optimizations on the database, but to no avail. > The query: > {code:sql} > SELECT task_instance.dag_id AS task_instance_dag_id, task_instance.state AS > task_instance_state, count(task_instance.task_id) AS count_1 FROM > task_instance LEFT OUTER JOIN (SELECT dag_run.dag_id AS dag_id, > dag_run.execution_date AS execution_date FROM dag_run WHERE dag_run.state = > 'running') AS running_dag_run ON running_dag_run.dag_id = > task_instance.dag_id AND running_dag_run.execution_date = > task_instance.execution_date LEFT OUTER JOIN (SELECT dag_run.dag_id AS > dag_id, max(dag_run.execution_date) AS execution_date FROM dag_run GROUP BY > dag_run.dag_id) AS last_dag_run ON last_dag_run.dag_id = task_instance.dag_id > AND last_dag_run.execution_date = task_instance.execution_date WHERE > task_instance.task_id IN ... AND (running_dag_run.dag_id IS NOT NULL OR > last_dag_run.dag_id IS NOT NULL) GROUP BY task_instance.dag_id, > task_instance.state; > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (AIRFLOW-246) dag_stats endpoint has a terrible query
[ https://issues.apache.org/jira/browse/AIRFLOW-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15356998#comment-15356998 ] Matthias Huschle commented on AIRFLOW-246: -- Do I understand the query correctly, that it delivers different results than before, as it double counts the TI belonging to the last DAG run if it is still running? Not that I'd consider this a bad trade-off, but it might be worth noting it. > dag_stats endpoint has a terrible query > --- > > Key: AIRFLOW-246 > URL: https://issues.apache.org/jira/browse/AIRFLOW-246 > Project: Apache Airflow > Issue Type: Bug > Components: webserver >Affects Versions: Airflow 1.7.1 > Environment: MySQL Backend through sqlalchemy >Reporter: Neil Hanlon >Assignee: Kengo Seki > > Hitting this endpoint creates a series of queries on the database which take > over 20 seconds to run, causing the page to not load for that entire time. > Luckily the main page (which includes this under "Recent Statuses") loads > this synchronously, but still... waiting almost half a minute (at times more) > to see the statuses for dags is really not fun. > We have less than a million rows in the task_instance table--so it's not even > a problem with that. > Here's a query profile for the query: > https://gist.github.com/NeilHanlon/613f12724e802bc51c23fca7d46d28bf > We've done some optimizations on the database, but to no avail. > The query: > {code:sql} > SELECT task_instance.dag_id AS task_instance_dag_id, task_instance.state AS > task_instance_state, count(task_instance.task_id) AS count_1 FROM > task_instance LEFT OUTER JOIN (SELECT dag_run.dag_id AS dag_id, > dag_run.execution_date AS execution_date FROM dag_run WHERE dag_run.state = > 'running') AS running_dag_run ON running_dag_run.dag_id = > task_instance.dag_id AND running_dag_run.execution_date = > task_instance.execution_date LEFT OUTER JOIN (SELECT dag_run.dag_id AS > dag_id, max(dag_run.execution_date) AS execution_date FROM dag_run GROUP BY > dag_run.dag_id) AS last_dag_run ON last_dag_run.dag_id = task_instance.dag_id > AND last_dag_run.execution_date = task_instance.execution_date WHERE > task_instance.task_id IN ... AND (running_dag_run.dag_id IS NOT NULL OR > last_dag_run.dag_id IS NOT NULL) GROUP BY task_instance.dag_id, > task_instance.state; > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (AIRFLOW-246) dag_stats endpoint has a terrible query
[ https://issues.apache.org/jira/browse/AIRFLOW-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15356332#comment-15356332 ] Kengo Seki commented on AIRFLOW-246: [~nhanlon] the patch seems to be merged into master at https://github.com/apache/incubator-airflow/commit/a2ed55f2c40857efaaf1876de5bc7929cbfb3166. Thanks a lot [~bolke]! > dag_stats endpoint has a terrible query > --- > > Key: AIRFLOW-246 > URL: https://issues.apache.org/jira/browse/AIRFLOW-246 > Project: Apache Airflow > Issue Type: Bug > Components: webserver >Affects Versions: Airflow 1.7.1 > Environment: MySQL Backend through sqlalchemy >Reporter: Neil Hanlon >Assignee: Kengo Seki > > Hitting this endpoint creates a series of queries on the database which take > over 20 seconds to run, causing the page to not load for that entire time. > Luckily the main page (which includes this under "Recent Statuses") loads > this synchronously, but still... waiting almost half a minute (at times more) > to see the statuses for dags is really not fun. > We have less than a million rows in the task_instance table--so it's not even > a problem with that. > Here's a query profile for the query: > https://gist.github.com/NeilHanlon/613f12724e802bc51c23fca7d46d28bf > We've done some optimizations on the database, but to no avail. > The query: > {code:sql} > SELECT task_instance.dag_id AS task_instance_dag_id, task_instance.state AS > task_instance_state, count(task_instance.task_id) AS count_1 FROM > task_instance LEFT OUTER JOIN (SELECT dag_run.dag_id AS dag_id, > dag_run.execution_date AS execution_date FROM dag_run WHERE dag_run.state = > 'running') AS running_dag_run ON running_dag_run.dag_id = > task_instance.dag_id AND running_dag_run.execution_date = > task_instance.execution_date LEFT OUTER JOIN (SELECT dag_run.dag_id AS > dag_id, max(dag_run.execution_date) AS execution_date FROM dag_run GROUP BY > dag_run.dag_id) AS last_dag_run ON last_dag_run.dag_id = task_instance.dag_id > AND last_dag_run.execution_date = task_instance.execution_date WHERE > task_instance.task_id IN ... AND (running_dag_run.dag_id IS NOT NULL OR > last_dag_run.dag_id IS NOT NULL) GROUP BY task_instance.dag_id, > task_instance.state; > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (AIRFLOW-246) dag_stats endpoint has a terrible query
[ https://issues.apache.org/jira/browse/AIRFLOW-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15336365#comment-15336365 ] Kengo Seki commented on AIRFLOW-246: bq. Looks good to me. Query only takes ~4 seconds to run on our db (~750k rows). I'm glad to hear that. Thanks for confirming ;) bq. maybe it should also be looked at whether or not the whole thing should be rearchitected... both of the queries (original, and the one you wrote) are pretty ugly. Well, I'm not sure whether it should be, since I'm a newbie to Airflow. I've just started evaluation and contribution to Airflow a month ago. I hope Airflow experts give us some advice, workarounds, etc. I agree that these queries are not so readable, but I also think it's somewhat inevitable as far as using ORM such as SQLAlchemy. The original python code which generates the query in question is not so difficult to read to me. bq. Let me know if you get a code fix for this and I'd be happy to test it. Sure. I hope I can submit the first PR this weekend. > dag_stats endpoint has a terrible query > --- > > Key: AIRFLOW-246 > URL: https://issues.apache.org/jira/browse/AIRFLOW-246 > Project: Apache Airflow > Issue Type: Bug > Components: webserver >Affects Versions: Airflow 1.7.1 > Environment: MySQL Backend through sqlalchemy >Reporter: Neil Hanlon > > Hitting this endpoint creates a series of queries on the database which take > over 20 seconds to run, causing the page to not load for that entire time. > Luckily the main page (which includes this under "Recent Statuses") loads > this synchronously, but still... waiting almost half a minute (at times more) > to see the statuses for dags is really not fun. > We have less than a million rows in the task_instance table--so it's not even > a problem with that. > Here's a query profile for the query: > https://gist.github.com/NeilHanlon/613f12724e802bc51c23fca7d46d28bf > We've done some optimizations on the database, but to no avail. > The query: > {code:sql} > SELECT task_instance.dag_id AS task_instance_dag_id, task_instance.state AS > task_instance_state, count(task_instance.task_id) AS count_1 FROM > task_instance LEFT OUTER JOIN (SELECT dag_run.dag_id AS dag_id, > dag_run.execution_date AS execution_date FROM dag_run WHERE dag_run.state = > 'running') AS running_dag_run ON running_dag_run.dag_id = > task_instance.dag_id AND running_dag_run.execution_date = > task_instance.execution_date LEFT OUTER JOIN (SELECT dag_run.dag_id AS > dag_id, max(dag_run.execution_date) AS execution_date FROM dag_run GROUP BY > dag_run.dag_id) AS last_dag_run ON last_dag_run.dag_id = task_instance.dag_id > AND last_dag_run.execution_date = task_instance.execution_date WHERE > task_instance.task_id IN ... AND (running_dag_run.dag_id IS NOT NULL OR > last_dag_run.dag_id IS NOT NULL) GROUP BY task_instance.dag_id, > task_instance.state; > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Commented] (AIRFLOW-246) dag_stats endpoint has a terrible query
[ https://issues.apache.org/jira/browse/AIRFLOW-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15336229#comment-15336229 ] Neil Hanlon commented on AIRFLOW-246: - [~sekikn] Looks good to me. Query only takes ~4 seconds to run on our db (~750k rows). Obviously with more task instances the actual size of this query will increase which will require database tuning to allow it to run (max_allowed_packet) and all that... so maybe it should also be looked at whether or not the whole thing should be rearchitected... both of the queries (original, and the one you wrote) are pretty ugly. I'm not saying all queries have to be pretty, but... Let me know if you get a code fix for this and I'd be happy to test it. (new query profile for posterity) {pre} airflow-rwdb01:airflow> show profile for query 1; ++--+ | Status | Duration | ++--+ | starting | 0.33 | | Waiting for query cache lock | 0.05 | | Waiting on query cache mutex | 0.04 | | checking query cache for query | 0.002673 | | checking permissions | 0.06 | | checking permissions | 0.04 | | checking permissions | 0.03 | | checking permissions | 0.06 | | Opening tables | 0.25 | | System lock| 0.001740 | | optimizing | 0.05 | | statistics | 0.17 | | preparing | 0.08 | | executing | 0.07 | | Sorting result | 0.04 | | Sending data | 0.000855 | | optimizing | 0.09 | | statistics | 0.09 | | preparing | 0.10 | | executing | 0.04 | | Sending data | 0.000622 | | optimizing | 0.73 | | statistics | 1.371602 | | preparing | 0.000239 | | executing | 0.08 | | Sending data | 0.407134 | | optimizing | 0.000145 | | statistics | 1.176737 | | preparing | 0.000174 | | executing | 0.06 | | Sending data | 0.395361 | | optimizing | 0.11 | | statistics | 0.14 | | preparing | 0.12 | | executing | 0.05 | | Sending data | 0.000654 | | removing tmp table | 0.21 | | Sending data | 0.13 | | Waiting for query cache lock | 0.05 | | Waiting on query cache mutex | 0.05 | | Sending data | 0.001048 | | init | 0.23 | | optimizing | 0.06 | | statistics | 0.07 | | preparing | 0.08 | | Creating tmp table | 0.000386 | | executing | 0.06 | | Copying to tmp table | 0.005354 | | Sorting result | 0.91 | | Sending data | 0.90 | | end| 0.04 | | removing tmp table | 0.000169 | | end| 0.06 | | query end | 0.07 | | closing tables | 0.04 | | removing tmp table | 0.07 | | closing tables | 0.04 | | removing tmp table | 0.07 | | closing tables | 0.04 | | removing tmp table | 0.05 | | closing tables | 0.13 | | freeing items | 0.000144 | | Waiting for query cache lock | 0.04 | | Waiting on query cache mutex | 0.03 | | freeing items | 0.57 | | Waiting for query cache lock | 0.04 | | Waiting on query cache mutex | 0.05 | | freeing items | 0.04 | | storing result in query cache | 0.07 | | logging slow query | 0.04 | | logging slow query | 0.000221 | | cleaning up| 0.13 | ++--+ 72 rows in set (0.00 sec) {pre} > dag_stats endpoint has a terrible query > --- > > Key: AIRFLOW-246 > URL: https://issues.apache.org/jira/browse/AIRFLOW-246 > Project: Apache Airflow > Issue Type: Bug > Components: webserver >Affects Versions: Airflow 1.7.1 > Environment: MySQL Backend through sqlalchemy >Reporter: Neil Hanlon > > Hitting this endpoint creates a series of queries on the database which take > over 20 seconds to run, causing the page to not load for that enti
[jira] [Commented] (AIRFLOW-246) dag_stats endpoint has a terrible query
[ https://issues.apache.org/jira/browse/AIRFLOW-246?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15335724#comment-15335724 ] Kengo Seki commented on AIRFLOW-246: Multiple left outer joins seem to affect performance. I think we can rewrite the query in question by replacing left outer join with inner join and union, such as: {code:sql} SELECT dag_id AS task_instance_dag_id, state AS task_instance_state, count(*) as count_1 FROM ( SELECT task_instance.dag_id, task_instance.state FROM task_instance JOIN ( SELECT dag_run.dag_id AS dag_id, dag_run.execution_date AS execution_date FROM dag_run WHERE dag_run.state = 'running' ) AS running_dag_run ON running_dag_run.dag_id = task_instance.dag_id AND running_dag_run.execution_date = task_instance.execution_date WHERE task_id IN ... UNION ALL SELECT task_instance.dag_id, task_instance.state FROM task_instance JOIN ( SELECT dag_run.dag_id AS dag_id, max(dag_run.execution_date) AS execution_date FROM dag_run GROUP BY dag_run.dag_id ) AS last_dag_run ON last_dag_run.dag_id = task_instance.dag_id AND last_dag_run.execution_date = task_instance.execution_date WHERE task_id IN ... ) t GROUP BY dag_id, state; {code} I compared these queries with some dummy data, and got x3-4 improvement. {code} mysql> select count(*) from dag_run; +--+ | count(*) | +--+ | 3417 | +--+ 1 row in set (0.00 sec) mysql> select count(*) from task_instance; +--+ | count(*) | +--+ | 229089 | +--+ 1 row in set (0.00 sec) mysql> SELECT task_instance.dag_id AS task_instance_dag_id, task_instance.state AS task_instance_state, count(task_instance.task_id) AS count_1 FROM task_instance LEFT OUTER JOIN (SELECT dag_run.dag_id AS dag_id, dag_run.execution_date AS execution_date FROM dag_run WHERE dag_run.state = 'running') AS running_dag_run ON running_dag_run.dag_id = task_instance.dag_id AND running_dag_run.execution_date = task_instance.execution_date LEFT OUTER JOIN (SELECT dag_run.dag_id AS dag_id, max(dag_run.execution_date) AS execution_date FROM dag_run GROUP BY dag_run.dag_id) AS last_dag_run ON last_dag_run.dag_id = task_instance.dag_id AND last_dag_run.execution_date = task_instance.execution_date WHERE task_instance.task_id IN ('all_success', 'also_run_this', 'always_true_1', 'always_true_2', 'bash_task', 'branching', 'branch_a', 'branch_b', 'branch_c', 'branch_d', 'condition', 'condition_is_False', 'condition_is_True', 'del_op', 'end', 'false_1', 'false_2', 'final_1', 'final_2', 'follow_branch_a', 'follow_branch_b', 'follow_branch_c', 'follow_branch_d', 'get_op', 'http_sensor_check', 'join', 'one_success', 'oper_1', 'oper_2', 'post_op', 'post_op_formenc', 'print_date', 'puller', 'push', 'push_by_returning', 'put_op', 'runme_0', 'runme_1', 'runme_2', 'run_after_loop', 'run_this', 'run_this_first', 'run_this_last', 'section-1', 'section-1-task-1', 'section-1-task-2', 'section-1-task-3', 'section-1-task-4', 'section-1-task-5', 'section-2', 'section-2-task-1', 'section-2-task-2', 'section-2-task-3', 'section-2-task-4', 'section-2-task-5', 'skip_operator_1', 'skip_operator_2', 'sleep', 'some-other-task', 'start', 'templated', 'test_trigger_dagrun', 'true_1', 'true_2') AND (running_dag_run.dag_id IS NOT NULL OR last_dag_run.dag_id IS NOT NULL) GROUP BY task_instance.dag_id, task_instance.state; +-+-+-+ | task_instance_dag_id| task_instance_state | count_1 | +-+-+-+ | example_bash_operator | success | 6 | | example_branch_dop_operator_v3 | NULL| 3 | | example_branch_operator | skipped | 6 | | example_branch_operator | success | 5 | | example_http_operator | failed | 1 | | example_http_operator | upstream_failed | 5 | | example_passing_params_via_test_command | success | 2 | | example_short_circuit_operator | skipped | 2 | | example_short_circuit_operator | success | 4 | | example_skip_dag| skipped | 4 | | example_skip_dag| success | 4 | | example_subdag_operator | success | 5 | | example_trigger_controller_dag | success | 1 | | example_trigger_target_dag | success | 2 | | example_xcom| success | 3 | | tutorial