apache/cassandra · error · java.lang.IllegalArgumentException

Threshold value for gc_concurrent_phase_warn_threshold

Error message

Threshold value for gc_concurrent_phase_warn_threshold (%d) must be greater than gc_concurrent_phase_log_threshold which is currently %d

What it means

setGCConcurrentPhaseWarnThreshold requires that a non-zero warn threshold be strictly greater than the current gc_concurrent_phase_log_threshold, mirroring the log-threshold check. A warn threshold <= the log threshold would make the warning impossible to trigger before logging, so it is rejected.

Solutions

1. Raise the warn threshold strictly above getGCConcurrentPhaseLogThreshold()
2. Lower the log threshold first via setGCConcurrentPhaseLogThreshold
3. Set the warn threshold to 0 to disable it

Example fix

// before
DatabaseDescriptor.setGCConcurrentPhaseLogThreshold(10000);
DatabaseDescriptor.setGCConcurrentPhaseWarnThreshold(5000); // throws
// after
DatabaseDescriptor.setGCConcurrentPhaseWarnThreshold(20000);
DatabaseDescriptor.setGCConcurrentPhaseLogThreshold(10000);

if (warnMs != 0 && warnMs <= DatabaseDescriptor.getGCConcurrentPhaseLogThreshold()) throw new IllegalArgumentException("gc_concurrent_phase_warn_threshold must exceed log threshold");

try { DatabaseDescriptor.setGCConcurrentPhaseWarnThreshold(warn); } catch (IllegalArgumentException e) { logger.error("gc threshold ordering violated: {}", e.getMessage()); }

When it happens

Trigger: Calling setGCConcurrentPhaseWarnThreshold(threshold) where threshold != 0 and threshold <= getGCConcurrentPhaseLogThreshold(); e.g. warn=5000 with log=10000.

Common situations: Config edits where gc_concurrent_phase_warn_threshold was lowered below or set equal to gc_concurrent_phase_log_threshold; programmatic setters called out of order.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

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

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/0073f4a83b04db56. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/config/DatabaseDescriptor.java:5084

            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;
    }

    public static boolean getCDCBlockWrites()
    {

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