risingwavelabs/risingwave · error

unsupported PostgreSQL snapshot data type {data_type} for co

Error message

unsupported PostgreSQL snapshot data type {data_type} for column `{name}`

What it means

Raised when the target RisingWave column type is Serial, Map, or Variant, none of which can be decoded from a PostgreSQL snapshot by this converter. The bail happens in the catch-all arm before any cell decode. These RW types have no defined Postgres snapshot representation in the connector.

Source

Thrown at src/connector/src/parser/postgres.rs:221

                bail!("unsupported PostgreSQL snapshot list element type {elem}")
            }
            _ => {
                match row
                    .try_get::<_, Option<ScalarAdapter>>(i)
                    .with_context(|| {
                        format!("failed to decode PostgreSQL snapshot list column `{name}`")
                    })? {
                    Some(value) => value.into_scalar(data_type).map(Some).ok_or_else(|| {
                        anyhow!(
                            "failed to convert PostgreSQL snapshot column `{name}` to {data_type}"
                        )
                    }),
                    None => Ok(None),
                }
            }
        },
        DataType::Serial | DataType::Map(_) | DataType::Variant => {
            bail!("unsupported PostgreSQL snapshot data type {data_type} for column `{name}`")
        }
    }
}

#[cfg(test)]
mod tests {
    use tokio_postgres::NoTls;

    use crate::parser::postgres::PgVectorAdapter;
    use crate::parser::scalar_adapter::EnumString;
    const DB: &str = "postgres";
    const USER: &str = "kexiang";

    #[test]
    fn test_pg_vector_adapter_parse_binary() {
        let mut raw = vec![];
        // dim = 3
        raw.extend_from_slice(&(3u16.to_be_bytes()));

View on GitHub (pinned to 6469eb736d)

Solutions

1. Change the RW column type to a supported one — e.g. map Postgres JSON/JSONB to varchar instead of Variant.
2. Recreate the RW table without Serial/Map/Variant columns for Postgres CDC snapshots.
3. Cast unsupported Postgres columns to text in the source and declare them as varchar in RW.
4. Upgrade RisingWave in case newer versions support the type for Postgres snapshots.

Example fix

-- before
CREATE TABLE t (attrs map<varchar, varchar>) FROM pg ...;
-- after: read JSON as text
CREATE TABLE t (attrs varchar) FROM pg ...;

fn unsupported_for_pg_snapshot(dt: &DataType) -> bool {
    matches!(dt, DataType::Serial | DataType::Map(_) | DataType::Variant)
}

fn unsupported_for_pg_snapshot(dt: &DataType) -> bool {
    matches!(dt, DataType::Serial | DataType::Map(_) | DataType::Variant)
}

match result {
    Err(e) if e.to_string().contains("unsupported PostgreSQL snapshot data type") => {
        // change column to varchar (JSON as text) and recreate the table
    }
    other => other?,
}

When it happens

Trigger: `postgres_cell_to_scalar_impl_strict` falls through to `DataType::Serial | DataType::Map(_) | DataType::Variant` during snapshot reads (`postgres_row_to_owned_row_with_strict_pk`, `min_and_max`, `next_split_right_bound_exclusive`, `next_greater_bound`).

Common situations: RW table created with a Map/Variant column over a Postgres source (e.g. JSON/JSONB mapped to Variant); schema inference produced Serial or Map from a Postgres type; snapshots of tables whose inferred schema includes these unsupported types.

Related errors

• unsupported postgres type: {}
• Postgres table should define the primary key for non-append-
• {:?} data type is not supported
• unsupported data type: {}, set to null
• unsupported PostgreSQL snapshot list element type {elem}

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/b7ba4f426e8a4808. Report an issue: GitHub.