risingwavelabs/risingwave · error · ParserError

backfill order strategy

Error message

backfill order strategy

What it means

Raised by `parse_backfill_order_strategy` when parsing a backfill order strategy specification (RisingWave-specific ALTER/CREATE syntax). The parser accepts DEFAULT, NONE, AUTO, or FIXED (<table pairs>); any other token fails and produces 'expected backfill order strategy'. It indicates the strategy keyword clause is missing or malformed.

Source

Thrown at src/sqlparser/src/parser.rs:4331

            )
            .map(|list: Vec<SetVariableValueSingle>| {
                if list.len() == 1 {
                    SetVariableValue::Single(list[0].clone())
                } else {
                    SetVariableValue::List(list)
                }
            }),
        ))
        .parse_next(self)
    }

    fn parse_backfill_order_strategy(&mut self) -> ModalResult<BackfillOrderStrategy> {
        alt((
            Keyword::DEFAULT.value(BackfillOrderStrategy::Default),
            Keyword::NONE.value(BackfillOrderStrategy::None),
            Keyword::AUTO.value(BackfillOrderStrategy::Auto),
            Self::parse_fixed_backfill_order.map(BackfillOrderStrategy::Fixed),
            fail.expect("backfill order strategy"),
        ))
        .parse_next(self)
    }

    fn parse_fixed_backfill_order(&mut self) -> ModalResult<Vec<(ObjectName, ObjectName)>> {
        self.expect_word("FIXED")?;
        self.expect_token(&Token::LParen)?;
        let edges = separated(
            0..,
            separated_pair(
                Self::parse_object_name,
                Token::Op("->".to_owned()),
                Self::parse_object_name,
            ),
            Token::Comma,
        )
        .parse_next(self)?;
        self.expect_token(&Token::RParen)?;

View on GitHub (pinned to 6469eb736d)

Solutions

1. Use one of the supported strategies: DEFAULT, NONE, AUTO, or FIXED `(<table> AS <table>, ...)`.
2. If using FIXED, verify the FIXED keyword and the parenthesized table-pair list follow exactly.
3. Check the RisingWave version's supported backfill order syntax and update the DDL.

Example fix

// before
ALTER TABLE t BACKFILL ORDER BY a;
// after
ALTER TABLE t BACKFILL ORDER FIXED (src AS t);

const STRATEGIES = new Set(['DEFAULT','NONE','AUTO']);
function validBackfillStrategy(clause) { return STRATEGIES.has(clause.toUpperCase()) || /^FIXED\s*\(/i.test(clause); }

When it happens

Trigger: Parsing a statement with a `backfill order` clause whose strategy token is misspelled or missing, e.g. `BACKFILL ORDER BY ...` instead of `BACKFILL ORDER FIXED (...)`, or an empty clause.

Common situations: Hand-written RisingWave DDL with a typo in FIXED/DEFAULT/NONE/AUTO; older SQL scripts using a backfill syntax from a different RisingWave version; copy-paste from documentation of another feature.

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.

Related errors

• Invalid input syntax: {0}
• {0}
• ROWS, RANGE, or GROUPS
• BOTH, LEADING, or TRAILING
• date/time field

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/b146402cd0cd39a2. Report an issue: GitHub.