apache/cassandra · error · java.lang.IllegalArgumentException

Threshold value for gc_concurrent_phase_warn_threshold must…

Error message

Threshold value for gc_concurrent_phase_warn_threshold must be greater than or equal to 0

What it means

setGCConcurrentPhaseWarnThreshold rejects negative values. The warn threshold (in ms) must be >= 0, where 0 disables it; negative ints indicate a bad config or conversion bug and throw IllegalArgumentException.

Solutions

1. Pass a non-negative threshold (0 disables the warning)
2. Fix negative values in cassandra.yaml
3. Check for integer overflow in unit conversion code before calling

Example fix

// before
DatabaseDescriptor.setGCConcurrentPhaseWarnThreshold(-500);
// after
DatabaseDescriptor.setGCConcurrentPhaseWarnThreshold(0); // or a positive ms value

if (threshold < 0) throw new IllegalArgumentException("gc_concurrent_phase_warn_threshold must be >= 0");

try { DatabaseDescriptor.setGCConcurrentPhaseWarnThreshold(v); } catch (IllegalArgumentException e) { logger.error("invalid gc_concurrent_phase_warn_threshold: {}", e.getMessage()); }

When it happens

Trigger: Calling setGCConcurrentPhaseWarnThreshold with a negative int, e.g. from an int overflow after unit conversion or a typo like -1000 in cassandra.yaml.

Common situations: Overflow when converting larger time units to ms, or hand-edited config with a negative duration.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• Threshold must be greater than 0
• Threshold must be less than Integer.MAX_VALUE
• Threshold value for gc_concurrent_phase_log_threshold
• Threshold value for gc_concurrent_phase_warn_threshold
• Threshold value for gc_warn_threshold

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/7b44287f93a90200. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/config/DatabaseDescriptor.java:5080

            throw new IllegalArgumentException("Threshold must be greater than 0");

        long gcConcurrentPhaseWarnThresholdInMs = getGCConcurrentPhaseWarnThreshold();
        if (gcConcurrentPhaseWarnThresholdInMs != 0 && threshold > gcConcurrentPhaseWarnThresholdInMs)
            throw new IllegalArgumentException("Threshold value for gc_concurrent_phase_log_threshold (" + threshold + ") must be less than gc_concurrent_phase_warn_threshold which is currently "
                                               + gcConcurrentPhaseWarnThresholdInMs);

        conf.gc_concurrent_phase_log_threshold = new DurationSpec.IntMillisecondsBound(threshold);
    }

    public static int getGCConcurrentPhaseWarnThreshold()
    {
        return conf.gc_concurrent_phase_warn_threshold.toMilliseconds();
    }

    public static void setGCConcurrentPhaseWarnThreshold(int threshold)
    {
        if (threshold < 0)
            throw new IllegalArgumentException("Threshold value for gc_concurrent_phase_warn_threshold must be greater than or equal to 0");

        long gcConcurrentPhaseLogThresholdInMs = getGCConcurrentPhaseLogThreshold();
        if (threshold != 0 && threshold <= gcConcurrentPhaseLogThresholdInMs)
            throw new IllegalArgumentException("Threshold value for gc_concurrent_phase_warn_threshold (" + threshold + ") must be greater than gc_concurrent_phase_log_threshold which is currently "
                                               + gcConcurrentPhaseLogThresholdInMs);

        conf.gc_concurrent_phase_warn_threshold = new DurationSpec.IntMillisecondsBound(threshold);
    }

    public static boolean isCDCEnabled()
    {
        return conf.cdc_enabled;
    }

    @VisibleForTesting
    public static void setCDCEnabled(boolean cdc_enabled)
    {
        conf.cdc_enabled = cdc_enabled;

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