What causes "failed to parse meta backend: {}" in risingwavelabs/risingwave?

Check the connection definition and set meta_store_backend to an accepted value: 'postgres' or 'mysql'

failed to parse meta backend

Error message

failed to parse meta backend: {}

What it means

When resolving the Iceberg connection's endpoint, RisingWave parses the meta store backend name from the connection parameters via `MetaBackend::from_str`. If the string is not a recognized backend (e.g. misspelled or unsupported), the parse fails and this error reports the offending value.

Solutions

Check the connection definition and set meta_store_backend to an accepted value: 'postgres' or 'mysql'
Inspect the connection with `SHOW CONNECTIONS` / its parameters to confirm the backend string
Recreate the connection with corrected `CREATE CONNECTION ... WITH (type='iceberg', meta_store_backend='postgres', ...)`

Example fix

// before
CREATE CONNECTION c WITH (type='iceberg', meta_store_backend='postgress', ...);
// after
CREATE CONNECTION c WITH (type='iceberg', meta_store_backend='postgres', ...);

Defensive patterns

Strategy: validation

Validate before calling

-- inspect connection params before creating iceberg tables
SHOW CONNECTIONS;
-- confirm meta_store_backend is exactly 'postgres' or 'mysql'

Prevention

Use only documented meta_store_backend values when defining Iceberg connections
Copy connection definitions from official examples, not other engines' configs
Validate connections with a small test CREATE TABLE before production DDL

When it happens

Trigger: `CREATE TABLE ... WITH (engine='iceberg')` where the connection's catalog parameters contain a `meta_store_backend` value that is not one of the accepted variants (e.g. 'pg', 'postgres.jdbc', 'MySQL' with wrong casing).

Common situations: Typo in connection definition (`metastore_backend` value like 'postgress'); copying a Trino/Spark config value that RisingWave doesn't accept; the JDBC endpoint string in the connection params is malformed.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/7abc83d42ed08535. Report an issue: GitHub.

Appendix: source

Thrown at src/frontend/src/handler/create_table.rs:1984

                        .host_str()
                        .ok_or_else(|| {
                            ErrorCode::InternalError(
                                "failed to parse host from meta store endpoint".to_owned(),
                            )
                        })?
                        .to_owned();
                    let meta_store_port = meta_store_endpoint.port().ok_or_else(|| {
                        ErrorCode::InternalError(
                            "failed to parse port from meta store endpoint".to_owned(),
                        )
                    })?;
                    let meta_store_database = meta_store_endpoint
                        .path()
                        .trim_start_matches('/')
                        .to_owned();

                    let Ok(meta_backend) = MetaBackend::from_str(&meta_store_backend, true) else {
                        bail!("failed to parse meta backend: {}", meta_store_backend);
                    };

                    let catalog_uri = match meta_backend {
                        MetaBackend::Postgres => {
                            format!(
                                "jdbc:postgresql://{}:{}/{}",
                                meta_store_host, meta_store_port, meta_store_database
                            )
                        }
                        MetaBackend::Mysql => {
                            format!(
                                "jdbc:mysql://{}:{}/{}",
                                meta_store_host, meta_store_port, meta_store_database
                            )
                        }
                        MetaBackend::Sqlite | MetaBackend::Sql | MetaBackend::Mem => {
                            bail!(
                                "Unsupported meta backend for iceberg engine table: {}",

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