SavingFrame opened a new pull request, #57828:
URL: https://github.com/apache/airflow/pull/57828
DagRuns API page was extremely slow with large datasets due to unindexed
ORDER BY on start_date column. The nullsfirst CASE statement workaround
prevented index usage, forcing full table scans.
This change adds idx_dag_run_start_date index and removes the nullsfirst
logic. While NULLS FIRST DESC would be ideal, it cannot leverage the index.
Since there's no way to achieve both indexed performance and consistent NULL
ordering across PostgreSQL and MySQL, we accept the database defaults:
PostgreSQL orders NULLs first in DESC, MySQL orders NULLs last in DESC.
Fixes #57344
In the issue you can read full debugging description and tests results.
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