apache/cassandra · error · RuntimeException

KeyCacheSavePeriodInSeconds must be non-negative.

Error message

KeyCacheSavePeriodInSeconds must be non-negative.

What it means

CacheService.setKeyCacheSavePeriodInSeconds validates that the key-cache autosave interval is not negative before storing it and rescheduling the key cache saver. A negative value has no meaning as a periodic save interval, so the setter rejects it eagerly with an untyped RuntimeException. This setter is typically invoked via JMX at runtime rather than from application code.

Source

Thrown at src/java/org/apache/cassandra/service/CacheService.java:217

    public void setRowCacheSavePeriodInSeconds(int seconds)
    {
        if (seconds < 0)
            throw new RuntimeException("RowCacheSavePeriodInSeconds must be non-negative.");

        DatabaseDescriptor.setRowCacheSavePeriod(seconds);
        rowCache.scheduleSaving(seconds, DatabaseDescriptor.getRowCacheKeysToSave());
    }

    public int getKeyCacheSavePeriodInSeconds()
    {
        return DatabaseDescriptor.getKeyCacheSavePeriod();
    }

    public void setKeyCacheSavePeriodInSeconds(int seconds)
    {
        if (seconds < 0)
            throw new RuntimeException("KeyCacheSavePeriodInSeconds must be non-negative.");

        DatabaseDescriptor.setKeyCacheSavePeriod(seconds);
        keyCache.scheduleSaving(seconds, DatabaseDescriptor.getKeyCacheKeysToSave());
    }

    public int getCounterCacheSavePeriodInSeconds()
    {
        return DatabaseDescriptor.getCounterCacheSavePeriod();
    }

    public void setCounterCacheSavePeriodInSeconds(int seconds)
    {
        if (seconds < 0)
            throw new RuntimeException("CounterCacheSavePeriodInSeconds must be non-negative.");

        DatabaseDescriptor.setCounterCacheSavePeriod(seconds);
        counterCache.scheduleSaving(seconds, DatabaseDescriptor.getCounterCacheKeysToSave());
    }

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Pass a non-negative value: clamp with Math.max(0, seconds) before calling the setter.
2. Use 0 to disable periodic key cache saving instead of a negative number.
3. Check the source of the value (config parsing, unit conversion) for sign errors.
4. If the intent is a disabled interval, also consider removing the runtime update entirely so the cassandra.yaml value is kept.

Example fix

// before
cacheService.setKeyCacheSavePeriodInSeconds(getInterval());
// after
int seconds = getInterval();
if (seconds >= 0)
    cacheService.setKeyCacheSavePeriodInSeconds(seconds);

if (seconds < 0) throw new IllegalArgumentException("KeyCacheSavePeriodInSeconds must be >= 0");
cacheService.setKeyCacheSavePeriodInSeconds(seconds);

When it happens

Trigger: Calling CacheService.setKeyCacheSavePeriodInSeconds(seconds) with seconds < 0, e.g. via JMX (org.apache.cassandra.service.CacheService mbean) or internal code passing a negative duration value.

Common situations: Operators pushing a runtime JMX config change computed from a bad expression (e.g. unit conversion yielding a negative number), scripts that subtract timestamps, or hand-editing JMX console fields with a minus sign.

Related errors

• CounterCacheSavePeriodInSeconds must be non-negative.
• RowCacheKeysToSave must be non-negative.
• KeyCacheKeysToSave must be non-negative.
• CounterCacheKeysToSave must be non-negative.
• capacity should not be negative.

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/2f779902bb8f4c7c. Report an issue: GitHub.