elastic/elasticsearch · error · IllegalArgumentException

failed to parse [{}], fractional time values are not support

Error message

failed to parse [{}], fractional time values are not supported

What it means

Thrown by TimeValue.parse when the numeric prefix of a time value fails Long.parseLong but succeeds as Double.parseDouble — i.e. the user supplied a fractional number. TimeValue stores durations as a long plus a TimeUnit, so fractional values are fundamentally unsupported. The original NumberFormatException is chained as the cause for diagnostics.

Source

Thrown at libs/core/src/main/java/org/elasticsearch/core/TimeValue.java:429

        final String s = normalized.substring(0, normalized.length() - suffix.length()).trim();
        try {
            final long value = Long.parseLong(s);
            if (value < -1) {
                // -1 is magic, but reject any other negative values
                throw new IllegalArgumentException(
                    "failed to parse setting ["
                        + settingName
                        + "] with value ["
                        + initialInput
                        + "] as a time value: negative durations are not supported"
                );
            }
            return value;
        } catch (final NumberFormatException e) {
            try {
                @SuppressWarnings("unused")
                final double ignored = Double.parseDouble(s);
                throw new IllegalArgumentException("failed to parse [" + initialInput + "], fractional time values are not supported", e);
            } catch (final NumberFormatException ignored) {
                throw new IllegalArgumentException("failed to parse [" + initialInput + "]", e);
            }
        }
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        return this.compareTo(((TimeValue) o)) == 0;
    }

    @Override
    public int hashCode() {
        return Double.hashCode(((double) duration) * timeUnit.toNanos(1));
    }

View on GitHub (pinned to db6a809a66)

Solutions

1. Round or truncate to a whole number of the smallest needed unit, e.g. convert 1.5s to 1500ms.
2. If the source is a double, scale and cast: long ms = (long) Math.round(seconds * 1000); then format ms + "ms".
3. Replace the fractional literal in elasticsearch.yml or the settings API with an integer-equivalent duration.
4. Validate user-supplied time strings with a regex like ^-?\d+[a-z]+$ before forwarding them to TimeValue.

Example fix

// before
String t = "1.5s";
TimeValue.parseTimeValue(t, "x");

// after — scale to milliseconds
String t = Math.round(1.5 * 1000) + "ms"; // "1500ms"

// Reject fractional magnitudes before parsing
static String requireIntegralDuration(String s) {
    String body = s.toLowerCase(Locale.ROOT).trim().replaceAll("(ns|us|micros|ms|s|m|h|d)$", "");
    if (body.matches(".*[.e].*")) throw new IllegalArgumentException("fractional not allowed: " + s);
    return s;
}

static boolean isIntegralTimeValue(String s) {
    if (s == null) return false;
    String n = s.trim().toLowerCase(Locale.ROOT);
    return n.matches("-?\\d+(ns|us|micros|ms|s|m|h|d)") || n.equals("-1") || n.matches("0+");
}

try {
    TimeValue.parseTimeValue(raw, setting);
} catch (IllegalArgumentException e) {
    if (e.getMessage().contains("fractional")) {
        // rescale: parse the double, convert to smallest integer unit
    } else {
        throw e;
    }
}

When it happens

Trigger: Passing a fractional duration string such as "1.5s", "0.5d", "2.25h", ".5ms" to any code path that calls TimeValue.parseTimeValue. Fires at TimeValue.java:429 in the inner try after Double.parseDouble(s) succeeds.

Common situations: Converting a float/double timeout (e.g. from a JSON payload or a metrics-derived value) directly to a string without rounding. Migrating configs from systems that accept fractional seconds (Python's timedelta, ISO-8601 durations). Tooling that does String.valueOf(2.5) + "s".

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 setting [{}] with value [{}] as a time value
• failed to parse [{}]
• failed to parse setting [{}] with value [{}] as a time value
• Failed to parse value [{}] as only [true] or [false] are all
• duration cannot be negative, was given [{}]

AI-assisted analysis of elastic/elasticsearch@db6a809a66 (2026-08-12). Data as JSON: /api/errors/ac7c5b201b1db93c. Report an issue: GitHub.