risingwavelabs/risingwave · error · ErrorCode

Cannot compare in memory

Error message

Cannot compare in memory: {0}

What it means

FrontendError::MemComparableError, converted from a memcomparable::Error: serializing or deserializing a value to/from the memcomparable encoding (used for in-memory ordering, e.g. TopN/merge sort keys) failed. Typically indicates an unsupported or corrupted value in a sort key.

Solutions

  1. Inspect the underlying memcomparable::Error for which value failed to encode/decode in comparable form.
  2. Ensure the data types being ordered/compared are supported by memcomparable encoding.
  3. Check for corrupted key bytes or mismatched schema between writer and reader.
Defensive patterns

Strategy: try-catch

When it happens

Trigger: Thrown at src/frontend/src/error.rs:163 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/38441b9f914cfb93. Report an issue: GitHub.

Appendix: source

Thrown at src/frontend/src/error.rs:163

        #[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}")]
    InsertViolation(String),
    #[error("Invalid input syntax: {0}")]
    InvalidInputSyntax(#[message] String),
    #[error("Cannot compare in memory: {0}")]
    MemComparableError(#[from] memcomparable::Error),
    #[error("Error while de/se values: {0}")]
    ValueEncodingError(
        #[from]
        #[backtrace]
        ValueEncodingError,
    ),
    #[error("Invalid value `{config_value}` for `{config_entry}`")]
    InvalidConfigValue {
        config_entry: String,
        config_value: String,
    },
    #[error("Invalid parameter value: {0}")]
    InvalidParameterValue(String),
    #[error("Sink error: {0}")]
    SinkError(
        #[source]
        #[backtrace]

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