kaxil opened a new pull request #13893:
URL: https://github.com/apache/airflow/pull/13893


   closes https://github.com/apache/airflow/issues/13504
   
   Currently the DagFileProcessor parses the DAG files, writes it to the
   `dag` table and then writes DAGs to `serialized_dag` table.
   
   At the same time, the scheduler loop is constantly looking for the next
   DAGs to process based on ``next_dagrun_create_after`` column of the DAG
   table.
   
   It might happen that as soon as the DagFileProcessor writes DAG to `dag`
   table, the scheduling loop in the Scheduler picks up the DAG for preocessing.
   However, as the DagFileProcessor has not written to serialized DAG table yet
   the scheduler will error with "Serialized Dag not Found" error.
   
   This would mainly happen when the DAGs are dynamic where the result of one 
DAG,
   creates multiple DAGs.
   
   This commit changes the order of writing DAG and Serialized DAG and hence
   before a DAG is written to `dag` table it will be written to 
`serialized_dag` table.
   
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