What causes "missing required property 'port' for MySQL CDC source" in risingwavelabs/risingwave?

Add 'port' to the WITH/properties of the MySQL CDC source, e.g. port = '3306'.

missing required property 'port' for MySQL CDC source

Error message

missing required property 'port' for MySQL CDC source

What it means

The MySQL CDC binlog monitor requires a 'port' entry in the source's CDC properties map before it can connect to MySQL. When `monitor_mysql_binlog_files` looks up `properties.get("port")` and finds nothing, it fails fast with this anyhow error instead of attempting a connection to a default or unspecified port. It exists to surface an incomplete source definition early, in the background monitor loop.

Source

Thrown at src/connector/src/source/cdc/enumerator/mod.rs:424

    }
}

impl DebeziumSplitEnumerator<Mysql> {
    async fn monitor_mysql_binlog_files(&mut self) -> ConnectorResult<()> {
        // Get hostname and port for metrics labels
        let hostname = self
            .properties
            .get("hostname")
            .map(|s| s.as_str())
            .ok_or_else(|| {
                anyhow::anyhow!("missing required property 'hostname' for MySQL CDC source")
            })?;
        let port = self
            .properties
            .get("port")
            .map(|s| s.as_str())
            .ok_or_else(|| {
                anyhow::anyhow!("missing required property 'port' for MySQL CDC source")
            })?;

        // Query binlog files and update metrics
        let binlog_files = self.query_binlog_files().await.with_context(|| {
            format!(
                "failed to query binlog files for MySQL CDC source {} ({}:{})",
                self.source_id, hostname, port
            )
        })?;
        if let Some((oldest_file, oldest_size)) = binlog_files.first()
            && let Some(seq) = extract_binlog_file_seq(oldest_file)
        {
            let labels = vec![
                self.source_id.to_string(),
                hostname.to_owned(),
                port.to_owned(),
            ];
            get_or_create_guarded_int_gauge(

View on GitHub (pinned to 6469eb736d)

Solutions

Add 'port' to the WITH/properties of the MySQL CDC source, e.g. port = '3306'.
If building properties in code, insert("port".into(), port.to_string()) before constructing the enumerator.
Drop and recreate the source with the complete property set so the running monitor picks it up.

Example fix

// before
CREATE TABLE t (...) WITH (
  connector = 'mysql-cdc',
  hostname = 'mysql.example.com',
  username = 'u', password = 'p', database.name = 'db', table.name = 't'
);
// after
CREATE TABLE t (...) WITH (
  connector = 'mysql-cdc',
  hostname = 'mysql.example.com',
  port = '3306',
  username = 'u', password = 'p', database.name = 'db', table.name = 't'
);

Defensive patterns

Strategy: validation

Validate before calling

let required = ["hostname", "port", "username", "password", "database.name"];
assert!(required.iter().all(|k| props.contains_key(*k)), "missing 'port' (and check all of {:?}) in CDC properties", required);

Try / catch

match monitor_cdc_result {
    Err(e) if e.to_string().contains("missing required property 'port'") => {
        log::error!("CDC source misconfigured: add port to WITH options: {e}");
        // halt monitoring until source is recreated with full props
    }
    Err(e) => return Err(e),
    Ok(v) => Ok(v),
}

Prevention

Always include hostname, port, username, password, database.name and table.name in mysql-cdc WITH options.
Validate the properties map against a required-keys checklist before CREATE SOURCE.
Never assume defaults (like 3306) are applied server-side; set port explicitly.

When it happens

Trigger: A MySQL CDC source (CREATE SOURCE / CREATE TABLE ... WITH connector='mysql-cdc') is running and monitor_cdc spawns monitor_mysql_binlog_files, but the user's `properties` map passed to CdcSplitEnumerator has no 'port' key.

Common situations: Creating a CDC source without specifying the port (expecting the MySQL default 3306 to be assumed), building properties programmatically and skipping optional-looking keys, or upgrading from a version where the port was defaulted elsewhere.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/496162a2fd91643b. Report an issue: GitHub.