[AIRFLOW-6965] The get_task_instances method is performed three times during one creation of the DAGRun file.

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.10.9
• Component/s: scheduler
• Epic Link: scheduler-performance
• Assignee: Unassigned
• Reporter: Kamil Bregula
• Created: 01/Mar/20 10:35
• Updated: 01/Mar/20 13:49

Description

Hello,

Task_instances queries are executed three times. This is redundant. If we can limit the number of these queries, we can achieve performance improvements.

First query:

perform_file: https://github.com/apache/airflow/blob/cc562dd/airflow/jobs/scheduler_job.py#L792

process_dags: https://github.com/apache/airflow/blob/cc562dd/airflow/jobs/scheduler_job.py#L853

create_dag_run: https://github.com/apache/airflow/blob/cc562ddfc7a53932d89c92ee1fb8f780c1fb38e3/airflow/jobs/scheduler_job.py#L726

create_dagrun: https://github.com/apache/airflow/blob/cc562ddfc7a53932d89c92ee1fb8f780c1fb38e3/airflow/jobs/scheduler_job.py#L638

verify_integrity: https://github.com/apache/airflow/blob/cc562ddfc7a53932d89c92ee1fb8f780c1fb38e3/airflow/models/dag.py#L1454

get_task_instances: https://github.com/apache/airflow/blob/cc562ddfc7a53932d89c92ee1fb8f780c1fb38e3/airflow/models/dagrun.py#L436

Third query:

perform_file: https://github.com/apache/airflow/blob/cc562dd/airflow/jobs/scheduler_job.py#L792

process_dags: https://github.com/apache/airflow/blob/cc562dd/airflow/jobs/scheduler_job.py#L853

_process_task_instances: https://github.com/apache/airflow/blob/cc562dd/airflow/jobs/scheduler_job.py#L738

update_state: https://github.com/apache/airflow/blob/cc562ddfc7a53932d89c92ee1fb8f780c1fb38e3/airflow/jobs/scheduler_job.py#L685

get_task_instances: [https://github.com/apache/airflow/blob/cc562ddfc7a53932d89c92ee1fb8f780c1fb38e3/airflow/models/dagrun.py#L292
]

perform_file: https://github.com/apache/airflow/blob/cc562dd/airflow/jobs/scheduler_job.py#L792

process_dags: https://github.com/apache/airflow/blob/cc562dd/airflow/jobs/scheduler_job.py#L853

_process_task_instances: https://github.com/apache/airflow/blob/cc562dd/airflow/jobs/scheduler_job.py#L738

verify_integrity: https://github.com/apache/airflow/blob/cc562ddfc7a53932d89c92ee1fb8f780c1fb38e3/airflow/jobs/scheduler_job.py#L684

get_task_instances: https://github.com/apache/airflow/blob/cc562ddfc7a53932d89c92ee1fb8f780c1fb38e3/airflow/models/dagrun.py#L436

https://github.com/apache/airflow/blob/cc562ddfc7a53932d89c92ee1fb8f780c1fb38e3/airflow/models/dagrun.py#L292