ronaldorcampos opened a new pull request, #62139:
URL: https://github.com/apache/airflow/pull/62139
While debugging queries in my mysql server, I noticed that many slow queries
are originating from airflow
```
# Time: 2026-02-18T07:25:10.856389Z
# User@Host: airflow[airflow] @ [192.168.100.3] Id: 177446
# Query_time: 17.806845 Lock_time: 0.000006 Rows_sent: 1 Rows_examined: 2
SET timestamp=1771399493;
SELECT dag_run.id, dag_run.dag_id, dag_run.logical_date,
dag_run.data_interval_start, dag_run.data_interval_end
FROM dag_run, (SELECT dag_run.dag_id AS dag_id, max(dag_run.logical_date) AS
max_logical_date
FROM dag_run
WHERE dag_run.dag_id IN ('vmware_monitor_ingestion',
'vmware_ingest_monitor_data') AND dag_run.run_type IN ('backfill', 'scheduled')
GROUP BY dag_run.dag_id) AS anon_1
WHERE dag_run.dag_id = anon_1.dag_id AND dag_run.logical_date =
anon_1.max_logical_date;
```
For instance, running explain on the query above, it shows:
```
{
"data":
[
{
"id": 1,
"select_type": "PRIMARY",
"table": "<derived2>",
"partitions": null,
"type": "ALL",
"possible_keys": null,
"key": null,
"key_len": null,
"ref": null,
"rows": 68862,
"filtered": 100,
"Extra": "Using where"
},
{
"id": 1,
"select_type": "PRIMARY",
"table": "dag_run",
"partitions": null,
"type": "eq_ref",
"possible_keys":
"dag_run_dag_id_run_id_key,dag_run_dag_id_logical_date_key,idx_dag_run_dag_id,dag_id_state",
"key": "dag_run_dag_id_logical_date_key",
"key_len": "760",
"ref": "anon_1.dag_id,anon_1.max_logical_date",
"rows": 1,
"filtered": 100,
"Extra": null
},
{
"id": 2,
"select_type": "DERIVED",
"table": "dag_run",
"partitions": null,
"type": "index",
"possible_keys":
"dag_run_dag_id_run_id_key,dag_run_dag_id_logical_date_key,idx_dag_run_dag_id,idx_dag_run_queued_dags,dag_id_state,idx_dag_run_running_dags",
"key": "dag_run_dag_id_run_id_key",
"key_len": "1504",
"ref": null,
"rows": 685368,
"filtered": 10.05,
"Extra": "Using where"
}
]
}
```
The derived scans 685k+ rows, which is terrible performance wise, hence
giving 15-20s queries in my db.
Adding the new composite index, `dag_id_run_type_logical_date_key`, shows
```
"data":
[
{
"id": 1,
"select_type": "PRIMARY",
"table": "<derived2>",
"partitions": null,
"type": "ALL",
"possible_keys": null,
"key": null,
"key_len": null,
"ref": null,
"rows": 2,
"filtered": 100,
"Extra": "Using where"
},
{
"id": 1,
"select_type": "PRIMARY",
"table": "dag_run",
"partitions": null,
"type": "eq_ref",
"possible_keys":
"dag_run_dag_id_run_id_key,dag_run_dag_id_logical_date_key,idx_dag_run_dag_id,dag_id_state,dag_id_run_type_logical_date_key",
"key": "dag_run_dag_id_logical_date_key",
"key_len": "760",
"ref": "anon_1.dag_id,anon_1.max_logical_date",
"rows": 1,
"filtered": 100,
"Extra": null
},
{
"id": 2,
"select_type": "DERIVED",
"table": "dag_run",
"partitions": null,
"type": "range",
"possible_keys":
"dag_run_dag_id_run_id_key,dag_run_dag_id_logical_date_key,idx_dag_run_dag_id,idx_dag_run_queued_dags,dag_id_state,idx_dag_run_running_dags,dag_id_run_type_logical_date_key",
"key": "dag_id_run_type_logical_date_key",
"key_len": "904",
"ref": null,
"rows": 2,
"filtered": 100,
"Extra": "Using where; Using index for group-by"
}
]
}
```
The same query now runs in 150-200ms.
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