risingwavelabs/risingwave · error

missing `slot.name` in CDC properties

Error message

missing `slot.name` in CDC properties

What it means

CdcSplitEnumerator::query_postgres_lsns connects to the upstream PostgreSQL to read slot LSNs (used to monitor confirmed_flush_lsn for progress). It requires the CDC properties to contain `slot.name`; without it, the slot to query is unknown and this error is thrown.

Source

Thrown at src/connector/src/source/cdc/enumerator/mod.rs:244

            }
            None => {
                tracing::warn!(
                    "no replication slot was found while querying LSNs for source {}",
                    self.source_id
                );
            }
        };
        Ok(())
    }

    /// Query LSNs from PostgreSQL, return (`confirmed_flush_lsn`, `upstream_max_lsn`, `slot_name`).
    async fn query_postgres_lsns(&self) -> ConnectorResult<Option<(Option<u64>, u64, String)>> {
        let pg_conn = pg_connection_config_from_properties(&self.properties)?;

        let slot_name = self
            .properties
            .get("slot.name")
            .ok_or_else(|| anyhow::anyhow!("missing `slot.name` in CDC properties"))?;

        // No TCP keepalive for CDC enumerator
        let application_name = format!("risingwave-postgres-source-enumerator-{}", self.source_id);
        let client = create_pg_client(&pg_conn, None, Some(&application_name))
            .await
            .context("failed to create the PostgreSQL client")?;

        let query = "SELECT confirmed_flush_lsn, pg_current_wal_lsn() \
            FROM pg_replication_slots WHERE slot_name = $1";
        let row = client
            .query_opt(query, &[&slot_name])
            .await
            .context("failed to query PostgreSQL LSNs")?;
        match row {
            Some(row) => {
                let confirmed_flush_lsn: Option<PgLsn> = row.get(0);
                let upstream_max_lsn: PgLsn = row.get(1);
                Ok(Some((

View on GitHub (pinned to 6469eb736d)

Solutions

1. Add slot.name='<slot>' to the CDC source WITH clause (or recreate the source with it)
2. Check for misspellings such as slotname / slot_name — the key must be exactly 'slot.name'
3. Drop and recreate the source if persisted metadata is missing the key

Example fix

// before
WITH (connector='cdc', hostname='pg', database='mydb', ...)
// after
WITH (connector='cdc', hostname='pg', database='mydb', slot.name='rw_slot_1', ...)

if !cdc_props.contains_key("slot.name") {
    return Err(anyhow!("CDC properties require slot.name, e.g. slot.name='rw_slot_1'"));
}

When it happens

Trigger: Calling query_postgres_lsns (via monitor_postgres_confirmed_flush_lsn) on a Postgres CDC source whose properties map lacks the 'slot.name' key — e.g. the source was created without slot.name or with a misspelled key like slotname.

Common situations: Postgres CDC source created without slot.name option; renaming option keys between versions; manually constructed properties maps.

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

• PostgreSQL table {} exists, but the connection user `{}` doe
• Postgres table should define the primary key for non-append-
• {:?} data type is not supported
• unsupported encoding for DEBEZIUM_MONGO format
• unsupported encoding for Maxwell

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/e9e2f3a104789236. Report an issue: GitHub.