apache/cassandra · error · java.lang.IllegalArgumentException

Threshold value for gc_concurrent_phase_log_threshold

Error message

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

What it means

setGCConcurrentPhaseLogThreshold enforces ordering with the warn threshold: when a warn threshold is active (non-zero), the log threshold must be strictly less than it. A log threshold >= warn threshold is rejected because it would never fire before the warn condition.

Solutions

1. Lower the log threshold to be strictly less than getGCConcurrentPhaseWarnThreshold()
2. Raise gc_concurrent_phase_warn_threshold first via setGCConcurrentPhaseWarnThreshold
3. Set the warn threshold to 0 to disable the cross-check

Example fix

// before
DatabaseDescriptor.setGCConcurrentPhaseWarnThreshold(10000);
DatabaseDescriptor.setGCConcurrentPhaseLogThreshold(20000); // throws
// after
DatabaseDescriptor.setGCConcurrentPhaseWarnThreshold(30000);
DatabaseDescriptor.setGCConcurrentPhaseLogThreshold(20000);

if (logMs >= DatabaseDescriptor.getGCConcurrentPhaseWarnThreshold() && DatabaseDescriptor.getGCConcurrentPhaseWarnThreshold() != 0) throw new IllegalArgumentException("gc_concurrent_phase_log_threshold must be < warn threshold");

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

When it happens

Trigger: Calling setGCConcurrentPhaseLogThreshold(threshold) while getGCConcurrentPhaseWarnThreshold() is non-zero and threshold >= that warn threshold; e.g. log=20000 with warn=10000.

Common situations: cassandra.yaml where gc_concurrent_phase_log_threshold was raised above or set equal to gc_concurrent_phase_warn_threshold, or programmatic updates applied in the wrong 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_warn_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/32152c144431d24e. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/config/DatabaseDescriptor.java:5066

            throw new IllegalArgumentException("Threshold value for gc_warn_threshold (" + threshold + ") must be greater than gc_log_threshold which is currently "
                                               + gcLogThresholdInMs);

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

    public static int getGCConcurrentPhaseLogThreshold()
    {
        return conf.gc_concurrent_phase_log_threshold.toMilliseconds();
    }

    public static void setGCConcurrentPhaseLogThreshold(int threshold)
    {
        if (threshold <= 0)
            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 "

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