risingwavelabs/risingwave · error · ErrorCode

Protocol error

Error message

Protocol error: {0}

What it means

RisingWave frontend's ErrorCode::ProtocolError variant, rendered as "Protocol error: {0}". It signals a violation of the client-server protocol expectations (e.g. pgwire protocol or internal RPC message contracts) detected in the frontend layer. It carries a plain String message describing what was unexpected.

Solutions

1. Identify the client library and version from the connection and upgrade the driver to a current release.
2. Remove any TCP proxy/middleware between client and RisingWave to test a direct connection.
3. Capture the client traffic and compare the protocol message sequence against the Postgres wire protocol spec.
4. Report the reproducing driver/version to RisingWave if a supported driver triggers it.

Example fix

// before (very old driver)
pg = PG.connect(host: 'rw', dbname: 'dev') # old pg gem
// after
# upgrade driver: gem 'pg', '~> 1.5' then reconnect

// before connecting: check driver supports Postgres wire protocol v3
assert(driver.protocolVersion >= 3);

try { await conn.query(sql) } catch (e) {
  if (/Protocol error/.test(e.message)) { reconnect(); }
  else throw e;
}

When it happens

Trigger: Malformed or out-of-order pgwire wire messages from a client; a client sends an extended-protocol sequence the frontend does not expect; internal code explicitly calls ErrorCode::ProtocolError when a message/operation violates protocol assumptions.

Common situations: Buggy or very old client drivers speaking an unexpected Postgres protocol flow; proxies/middleware mangling wire traffic; mismatched driver/server version behavior.

Related errors

• get none metadata in commit response for coordinated sink…
• should get start response but get
• {0}
• ALTER SINK_RATE_LIMIT is not for sink into table
• ALTER SOURCE_RATE_LIMIT is not for table without source

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/a8ac5fa5822fc1b9. Report an issue: GitHub.

Appendix: source

Thrown at src/frontend/src/error.rs:141

        expr: String,
        #[source]
        #[backtrace]
        error: BoxedError,
    },
    #[error(transparent)]
    CastError(
        #[from]
        #[backtrace]
        CastError,
    ),
    #[error("Catalog error: {0}")]
    CatalogError(
        #[source]
        #[backtrace]
        #[message]
        BoxedError,
    ),
    #[error("Protocol error: {0}")]
    ProtocolError(#[message] String),
    #[error("Scheduler error: {0}")]
    SchedulerError(
        #[source]
        #[backtrace]
        BoxedError,
    ),
    #[error("Task not found")]
    TaskNotFound,
    #[error("Session not found")]
    SessionNotFound,
    #[error("Invalid reference: {0}")]
    InvalidReference(String),
    #[error("Item not found: {0}")]
    ItemNotFound(String),
    #[error("Duplicate Relation Name: {0}")]
    DuplicateRelationName(String),
    #[error("Invalid insert operation: {0}")]

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