risingwavelabs/risingwave · error · ConnectorError

Field ' ' is not allowed to be altered on the fly for sink

Error message

Field '{field}' is not allowed to be altered on the fly for sink: {sink_name}

What it means

Generated-code guard for `ALTER SINK`: the requested field is absent from SINK_ALLOW_ALTER_ON_FLY_FIELDS (or the JdbcSink-specific list) for that sink connector, so altering it without recreating the sink is rejected. Generic whitelist check over the field name.

Solutions

Alter only fields in the sink's allow_alter_on_fly registry.
Recreate the sink with the desired configuration instead of altering it.
Fix field name casing/typos.
Register the field as alterable and regenerate if it should be supported.

Example fix

// before
check_sink_allow_alter_on_fly_fields("kafka", &["topic".into()])?;
// after
DROP SINK s;
CREATE SINK s INTO kafka WITH (topic = 'new-topic');

Defensive patterns

Strategy: validation

Validate before calling

fn can_alter_sink(sink: &str, field: &str) -> bool {
    let allowed = if sink == JdbcSink::SINK_NAME {
        CONNECTION_ALLOW_ALTER_ON_FLY_FIELDS.get(JdbcSink::SINK_NAME)
    } else {
        sink_properties::sink_name_to_config_type_name(sink)
            .and_then(|t| SINK_ALLOW_ALTER_ON_FLY_FIELDS.get(t))
    };
    allowed.map(|f| f.contains(&field.to_string())).unwrap_or(false)
}

Try / catch

match check_sink_allow_alter_on_fly_fields(sink, &fields) {
    Err(e) => return Err(sql_error::unsupported(&format!("sink alter rejected: {e}"))),
    Ok(()) => proceed(),
}

Prevention

Recreate sinks for immutable option changes
Check the sink's registered alterable fields before ALTER
Match field names exactly

When it happens

Trigger: Validating an ALTER on a sink field not present in SINK_ALLOW_ALTER_ON_FLY_FIELDS for the given sink type.

Common situations: Attempting to change immutable sink options (e.g. Kafka topic, JDBC table) live; field-name typo; trying schema evolution the sink does not support.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/112bec645c9dd3c9. Report an issue: GitHub.

Appendix: source

Thrown at src/connector/src/with_options_test.rs:871

    let allowed_fields = if sink_name == JdbcSink::SINK_NAME {{
        CONNECTION_ALLOW_ALTER_ON_FLY_FIELDS.get(JdbcSink::SINK_NAME)
    }} else {{
        // Convert sink name to the type name key
        let Some(type_name) = sink_properties::sink_name_to_config_type_name(sink_name) else {{
            return Err(ConnectorError::from(anyhow::anyhow!(
                "Unknown sink connector: {{sink_name}}"
            )));
        }};
        SINK_ALLOW_ALTER_ON_FLY_FIELDS.get(type_name)
    }};
    let Some(allowed_fields) = allowed_fields else {{
        return Err(ConnectorError::from(anyhow::anyhow!(
            "No allow_alter_on_fly fields registered for sink: {{sink_name}}"
        )));
    }};
    for field in fields {{
        if !allowed_fields.contains(field) {{
            return Err(ConnectorError::from(anyhow::anyhow!(
                "Field '{{field}}' is not allowed to be altered on the fly for sink: {{sink_name}}"
            )));
        }}
    }}
    Ok(())
}}
"#,
        source_entries = source_entries,
        sink_entries = sink_entries
    )
}

View on GitHub (pinned to 6469eb736d)