risingwavelabs/risingwave · error

Unsupported encoding for Plain

Error message

Unsupported encoding for Plain

What it means

Raised in `PlainParser::new` when `FORMAT PLAIN` is configured with an encoding whose access builder is not supported. Plain (append-only) parsing only supports Json, Protobuf, Avro, and Bytes encodings; any other `EncodingProperties` variant (e.g. Debezium/DebeziumAvro/Maxwell/Canal-style encodings) is rejected at source creation time.

Source

Thrown at src/connector/src/parser/plain_parser.rs:71

    ) -> ConnectorResult<Self> {
        let key_builder = if let Some(key_column_name) = get_key_column_name(&rw_columns) {
            Some(AccessBuilderImpl::Bytes(BytesAccessBuilder::new(
                EncodingProperties::Bytes(BytesProperties {
                    column_name: Some(key_column_name),
                }),
            )?))
        } else {
            None
        };

        let payload_builder = match props.encoding_config {
            EncodingProperties::Json(_)
            | EncodingProperties::Protobuf(_)
            | EncodingProperties::Avro(_)
            | EncodingProperties::Bytes(_) => {
                AccessBuilderImpl::new_default(props.encoding_config).await?
            }
            _ => bail!("Unsupported encoding for Plain"),
        };

        let transaction_meta_builder = Some(AccessBuilderImpl::DebeziumJson(
            DebeziumJsonAccessBuilder::new(
                TimestamptzHandling::GuessNumberUnit,
                TimestampHandling::GuessNumberUnit,
                TimeHandling::Micro,
                BigintUnsignedHandlingMode::Long,
                false,
            )?,
        ));

        let schema_change_builder = Some(AccessBuilderImpl::DebeziumJson(
            DebeziumJsonAccessBuilder::new_for_schema_event()?,
        ));

        Ok(Self {
            key_builder,

View on GitHub (pinned to 6469eb736d)

Solutions

1. Use a supported encoding for FORMAT PLAIN: ENCODE JSON, PROTOBUF, AVRO, or BYTES.
2. If the data is Debezium change events, use `FORMAT DEBEZIUM-JSON` (or the matching Debezium format) instead of PLAIN.
3. Check the source DDL's FORMAT/ENCODE clauses and recreate the source with a valid combination.

Example fix

// before: invalid combination
CREATE SOURCE s (...) WITH (...) FORMAT PLAIN ENCODE DEBEZIUM-JSON;
// after: pick the right format
CREATE SOURCE s (...) WITH (...) FORMAT DEBEZIUM-JSON ENCODE JSON;
-- or: FORMAT PLAIN ENCODE JSON for append-only streams

-- Validate FORMAT/ENCODE combination before running DDL:
-- PLAIN supports only ENCODE JSON | PROTOBUF | AVRO | BYTES.
-- Debezium change streams must use FORMAT DEBEZIUM-JSON (or DEBEZIUM-AVRO).

When it happens

Trigger: Creating a source with `FORMAT PLAIN` combined with an unsupported encoding — for instance `FORMAT PLAIN ENCODE DEBEZIUM-JSON` or any encoding variant not in {Json, Protobuf, Avro, Bytes}.

Common situations: Misconfigured CREATE SOURCE statement pairing PLAIN with Debezium encodings; users intending CDC but choosing the wrong format; copy-pasted DDL from a Debezium example missing the ENCODE clause adjustment.

Related errors

• protobuf key is not supported
• empty payload with non-empty key
• decode utf8 error: {0}
• Parquet parser error: {message}
• {0}

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/6449467a72e7afe0. Report an issue: GitHub.