influxdata/influxdb · error · ValidationError

unsupported specifier found in time format

Error message

unsupported specifier found in time format "{0}" - supported specifiers: {1}

What it means

Thrown by `UnsupportedStrfTimeSpecifier` when the TimeFormat part of a partition template contains strftime specifiers the partitioning engine does not support. Only a limited set of specifiers (such as %Y, %m, %d, %H, %M) can be used, because each supported specifier must map to a physical partition key column.

Solutions

  1. Replace unsupported specifiers with supported ones only (%Y, %m, %d, %H and similar date/time components listed in the module docs).
  2. Move decorative text out of the format string or into the tag-based parts of the template.
  3. Before constructing the template, check the format against the supported-specifier list and reject invalid ones client-side.

Example fix

// before
Part::TimeFormat("%Y week %U".into())
// after
Part::TimeFormat("%Y-%m".into())
Defensive patterns

Strategy: validation

Validate before calling

const SUPPORTED: &[&str] = &["%Y", "%m", "%d", "%H", "%M"];
fn specifiers(fmt: &str) -> Vec<&str> {
    fmt.match_indices('%').filter_map(|(i, _)| fmt.get(i..i+2)).collect()
}
fn only_supported(fmt: &str) -> bool {
    specifiers(fmt).iter().all(|s| SUPPORTED.contains(s))
}

Try / catch

match PartitionTemplate::new(parts) {
    Err(e) if e.to_string().contains("unsupported specifier") => {
        eprintln!("use only supported strftime specifiers, e.g. %Y-%m-%d %H");
        Err(e.into())
    }
    other => other.map_err(Into::into),
}

Prevention

When it happens

Trigger: Creating a template with `Part::TimeFormat("%Y week %U")` or other exotic specifiers (%j, %U, %Z, timezones, etc.) via `PartitionTemplate::new` or the create-database API.

Common situations: Copying a strftime format from another system (cron, Python logging) that supports more specifiers; trying to embed literal % signs incorrectly; attempting timezone-aware formats.

Related errors

AI-assisted analysis of influxdata/influxdb@06200ef96b (2026-09-19). Data as JSON: /api/errors/e0d68693da2d8815. Report an issue: GitHub.

Appendix: source

Thrown at core/data_types/src/partition_template.rs:262

    /// This is not allowed
    ///
    /// [`TagValue`]: [`proto::template_part::Part::TagValue`]
    /// [`Bucket`]: [`proto::template_part::Part::Bucket`]
    #[error("tag name value cannot be repeated in partition template: {0}")]
    RepeatedTagValue(String),

    /// An attempt to make a new partition template without a [`TimeFormat`]
    /// part has been made. This is not allowed.
    ///
    /// [`TimeFormat`]: [`proto::template_part::Part::TimeFormat`]
    #[error("partition template must include a time format part")]
    TimeFormatPartRequired,

    /// The partition template defines a [`TimeFormat`] part, but the
    /// provided strftime formatter contains unsupported specifiers.
    ///
    /// [`TimeFormat`]: [`proto::template_part::Part::TimeFormat`]
    #[error("unsupported specifier found in time format \"{0}\" - supported specifiers: {1}")]
    UnsupportedStrfTimeSpecifier(String, String),

    /// The partition template defines a [`TimeFormat`] part, but the
    /// provided strftime format that is missing required specifiers.
    ///
    /// For example: using %m without %Y.
    ///
    /// [`TimeFormat`]: [`proto::template_part::Part::TimeFormat`]
    #[error("missing required specifier(s) in time format of partition template: {0}")]
    MissingRequiredStrfTimeSpecifier(String),
}

/// The maximum number of template parts a custom partition template may specify, to limit the
/// amount of space in the catalog used by the custom partition template and the partition keys
/// created with it.
pub const MAXIMUM_NUMBER_OF_TEMPLATE_PARTS: usize = 8;

/// The sentinel character used to delimit partition key parts in the partition

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