t8y2/dbx · error

failed to parse constraint %s columns: %w

Error message

failed to parse constraint %s columns: %w

What it means

While reading catalog constraint metadata rows, the value in the columns attribute (e.g. from sysconstraint) could not be parsed into a list of column numbers by parseCatalogAttributeNumbers. The driver wraps the underlying parse error with the constraint name so you know which catalog row is malformed.

Source

Thrown at agents/drivers/kingbase-go/kingbase_metadata.go:1874

		name, kind, definition        string
		columns, refColumns           []int
		refSchema, refTable           sql.NullString
		matchType, onUpdate, onDelete sql.NullString
		deferrable, initiallyDeferred bool
		valid, enabled                bool
	}
	raw := []rawConstraint{}
	for rows.Next() {
		var item rawConstraint
		var columnsRaw, refColumnsRaw, validRaw, statusRaw any
		if err := rows.Scan(&item.name, &item.kind, &item.definition, &columnsRaw, &item.refSchema, &item.refTable, &refColumnsRaw, &item.matchType, &item.onUpdate, &item.onDelete, &item.deferrable, &item.initiallyDeferred, &validRaw, &statusRaw); err != nil {
			return nil, err
		}
		item.valid = parseConstraintEnabled(validRaw)
		item.enabled = parseConstraintEnabled(statusRaw)
		item.columns, err = parseCatalogAttributeNumbers(columnsRaw)
		if err != nil {
			return nil, fmt.Errorf("failed to parse constraint %s columns: %w", item.name, err)
		}
		item.refColumns, err = parseCatalogAttributeNumbers(refColumnsRaw)
		if err != nil {
			return nil, fmt.Errorf("failed to parse constraint %s referenced columns: %w", item.name, err)
		}
		raw = append(raw, item)
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}

	attributes, err := s.relationAttributesByNumber(catalog, prefix, effective, table)
	if err != nil {
		return nil, err
	}
	refAttributes := map[string]map[int]string{}
	result := make([]constraintInfo, 0, len(raw))
	for _, item := range raw {

View on GitHub (pinned to c0390bff16)

Solutions

1. Check the underlying wrapped error to see which attribute value failed to parse
2. Verify the Kingbase server version is one supported by this driver version
3. Inspect the raw catalog value (e.g. SELECT the columns attribute for that constraint) to see the actual format
4. Update or patch the driver's parseCatalogAttributeNumbers to handle the server's attribute format
5. If the catalog row is corrupt, rebuild/validate that constraint or restore from a clean dump

Example fix

// before: driver fails on unexpected format
cols, err := parseCatalogAttributeNumbers(columnsRaw)
// after: guard and log the raw value before parsing
if columnsRaw == nil || strings.TrimSpace(fmt.Sprintf("%v", columnsRaw)) == "" {
    return nil, fmt.Errorf("constraint %s has empty columns attribute", item.name)
}
cols, err := parseCatalogAttributeNumbers(columnsRaw)

// Go: pre-check the catalog row before driver introspection
var cols sql.NullString
err := db.QueryRow(`SELECT conkey FROM pg_constraint WHERE conname=$1`, name).Scan(&cols)
if err != nil || !cols.Valid || cols.String == "" {
    return fmt.Errorf("constraint %s columns attribute missing", name)
}

conns, err := server.GetTableConstraints(ctx, schema, table)
if err != nil {
    var parseErr string
    if strings.Contains(err.Error(), "failed to parse constraint") {
        // fall back to raw catalog query or skip the malformed constraint
        return fallbackRawConstraints(db, schema, table)
    }
    return err
}

When it happens

Trigger: Calling metadata/DDL functions that list constraints (getTableConstraints/getTableDDL paths in kingbase_metadata.go) when the constraint's columns attribute is NULL, empty, or not a comma/brace-delimited numeric list the parser expects.

Common situations: Kingbase database versions whose catalog stores constraint column arrays in a different delimiter or encoding format; corrupted or partially-dumped catalogs; driver querying a system view whose column-format changed between Kingbase V8/V9 releases.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• failed to parse constraint %s referenced columns: %w
• list custom types in schema %q: %w
• trigger %q is ambiguous in schema %q; relation_name is requi
• materialized view %q.%q returned an empty source definition
• Hive driver does not expose HiveServer2 metadata RPCs

AI-assisted analysis of t8y2/dbx@c0390bff16 (2026-09-05). Data as JSON: /api/errors/9909874cf3d6e90b. Report an issue: GitHub.