risingwavelabs/risingwave · error · SinkError::DynamoDb

table {} key schema is empty

Error message

table {} key schema is empty

What it means

dynamodb_key_schema_names converts the DescribeTable key schema into key column names. DynamoDB normally guarantees at least one key element (HASH), so an empty key_schema means the AWS response lacked key information and the connector cannot align the RisingWave primary key with the table's key.

Source

Thrown at src/connector/src/sink/dynamodb.rs:421

                .fields()
                .get(*pk_idx)
                .map(|field| field.name.clone())
                .ok_or_else(|| {
                    SinkError::DynamoDb(anyhow!(
                        "RisingWave primary key column index {} is out of range",
                        pk_idx
                    ))
                })
        })
        .collect()
}

fn dynamodb_key_schema_names(
    table_name: &str,
    key_schema: &[KeySchemaElement],
) -> Result<Vec<String>> {
    if key_schema.is_empty() {
        return Err(SinkError::DynamoDb(anyhow!(
            "table {} key schema is empty",
            table_name
        )));
    }

    Ok(key_schema
        .iter()
        .map(|key_element| key_element.attribute_name().to_owned())
        .collect())
}

fn validate_pk_matches_dynamodb_key_schema(
    table_name: &str,
    rw_pk_names: &[String],
    dynamodb_keys: &[String],
) -> Result<()> {
    let rw_pk_set = rw_pk_names.iter().collect::<BTreeSet<_>>();
    let dynamodb_key_set = dynamodb_keys.iter().collect::<BTreeSet<_>>();

View on GitHub (pinned to 6469eb736d)

Solutions

1. Inspect the table with `aws dynamodb describe-table --table-name <name>` and confirm a valid KeySchema (HASH required).
2. Recreate the table with a proper key schema (HASH, optionally + RANGE).
3. Check the AWS SDK/endpoint used; a broken mock or proxy may strip key_schema.
4. If on dynamodb-local or a mock, fix the fixture to return a realistic DescribeTable response.

Example fix

// before: table created without key schema (invalid)
// after
aws dynamodb create-table --table-name events --key-schema AttributeName=pk,KeyType=HASH --attribute-definitions AttributeName=pk,AttributeType=S --provisioned-throughput ReadCapacityUnits=1,WriteCapacityUnits=1

aws dynamodb describe-table --table-name events --query 'Table.KeySchema'  # must contain at least one HASH key element

When it happens

Trigger: DescribeTable returns a table whose KeySchema is empty/absent — e.g. a malformed or partially provisioned table entry, or mocked/test endpoints returning incomplete responses.

Common situations: Testing against dynamodb-local or mocks returning incomplete DescribeTable output; corrupted/abnormally created tables; AWS SDK version responses lacking key_schema.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• table {} not found
• table {} is not active
• DynamoDB table {} primary key {:?} must match RisingWave pri
• No allow_alter_on_fly fields registered for sink: {sink_name
• Field '{field}' is not allowed to be altered on the fly for

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/992d60b89d923292. Report an issue: GitHub.