<a id="cmf-configure-sql"></a>

# Configure SQL Statements for Confluent Manager for Apache Flink

Confluent Manager for Apache Flink (CMF) provides several configuration properties that control the lifecycle
of SQL statements.

You can set these properties in your Helm values file under the `cmf.sql` key,
or pass them directly with `--set` during `helm install` or `helm upgrade`.

## Statement cleanup

CMF periodically removes old statements that have reached a terminal phase
(`COMPLETED` or `FAILED`). This prevents the metadata database
from growing indefinitely.

When cleanup runs, it deletes statement records that have been in a terminal phase
for longer than the configured retention period. Both the statement metadata and any
associated Kubernetes resources are removed.
Cleanup does not remove `INSERT INTO` statements or statement sets that were
deployed to a Flink cluster. It removes `SELECT` statements and statements that
CMF executes directly, such as `SHOW` and DDL statements.

| Property                                 | Default   | Description                                                                        |
|------------------------------------------|-----------|------------------------------------------------------------------------------------|
| `cmf.sql.statement-cleanup-enabled`      | `true`    | Enables periodic cleanup of old terminal statements.                               |
| `cmf.sql.statement-retention-days`       | `7`       | Number of days to retain terminal statements before they are eligible for cleanup. |
| `cmf.sql.statement-cleanup-interval-hrs` | `6`       | How often, in hours, the cleanup job runs.                                         |

## INSERT statement resource cleanup

When an `INSERT INTO` statement reaches the `COMPLETED` phase, CMF can
automatically delete the associated Flink deployment resources (such as FlinkDeployment
or FlinkSessionJob) from Kubernetes. This prevents resource leakage from completed
bounded INSERT jobs.

The statement record itself is retained in CMF and can still be queried through the
REST API or Confluent CLI. Only the underlying Kubernetes resources are removed.

#### NOTE
The Confluent Platform for Apache Flink Kubernetes Operator also provides a `kubernetes.operator.jm-deployment.shutdown-ttl`
configuration parameter that controls how long JobManager deployments are retained after a job
finishes. The CMF auto-cleanup acts immediately on completion, whereas the operator TTL is
time-based. When both are active, whichever triggers first removes the resources.

| Property                                        | Default   | Description                                                                                                        |
|-------------------------------------------------|-----------|--------------------------------------------------------------------------------------------------------------------|
| `cmf.sql.insert-statement-auto-cleanup-enabled` | `true`    | When enabled, Kubernetes deployment resources are deleted immediately after<br/>`INSERT INTO` statements complete. |

## SELECT statement auto-termination

`SELECT` statements run as Flink jobs that buffer results in memory. To prevent
idle `SELECT` statements from remaining on the cluster indefinitely when no client
is consuming their results, CMF can automatically terminate them after a
configurable timeout.

| Property                                                         | Default   | Description                                                                  |
|------------------------------------------------------------------|-----------|------------------------------------------------------------------------------|
| `cmf.sql.select-statement-auto-termination-enabled`              | `true`    | Enables automatic termination of idle `SELECT` statements.                   |
| `cmf.sql.select-statement-timeout-mins`                          | `10`      | Number of minutes before an idle `SELECT` statement is terminated.           |
| `cmf.sql.select-statement-auto-termination-check-frequency-mins` | `1`       | How often, in minutes, CMF checks for idle `SELECT` statements to terminate. |

## Example Helm configuration

The following example shows how to customize SQL statement behavior in your Helm
values file:

```yaml
# sql-values.yaml
cmf:
  sql:
    # Statement cleanup
    statement-cleanup-enabled: true
    statement-retention-days: 14
    statement-cleanup-interval-hrs: 12

    # INSERT resource cleanup
    insert-statement-auto-cleanup-enabled: true

    # SELECT auto-termination
    select-statement-auto-termination-enabled: true
    select-statement-timeout-mins: 15
    select-statement-auto-termination-check-frequency-mins: 2
```

You can also pass individual properties directly:

```bash
helm upgrade --install cmf confluentinc/confluent-manager-for-apache-flink \
  --set cmf.sql.statement-retention-days=14 \
  --set cmf.sql.select-statement-timeout-mins=15
```

## Related content

- [Manage Statements in Confluent Manager for Apache Flink](../jobs/sql-statements/manage-statements.md#flink-sql-statements-manage)
- [Create Statements with Confluent Manager for Apache Flink](../jobs/sql-statements/create-statements.md#flink-sql-statements-create)
- [Install Confluent Manager for Apache Flink with Helm](helm.md#install-cmf-helm)