apache/cassandra · error · ConfigurationException

Missing property value or default value is not set: ${key}

Error message

Missing property value or default value is not set: ${key}

What it means

Thrown by CassandraRelevantProperties.getLong() when a system property has neither a runtime value (System.getProperty returns null) nor a configured default. The property descriptor was declared without a default, so the library refuses to guess a long value.

Source

Thrown at src/java/org/apache/cassandra/config/CassandraRelevantProperties.java:931

     * @return System property value if it exists, defaultValue otherwise. Throws an exception if no default value is set.
     */
    public int getInt()
    {
        String value = System.getProperty(key);
        if (value == null && defaultVal == null)
            throw new ConfigurationException("Missing property value or default value is not set: " + key);
        return INTEGER_CONVERTER.convert(value == null ? defaultVal : value);
    }

    /**
     * Gets the value of a system property as a long.
     * @return System property value if it exists, defaultValue otherwise. Throws an exception if no default value is set.
     */
    public long getLong()
    {
        String value = System.getProperty(key);
        if (value == null && defaultVal == null)
            throw new ConfigurationException("Missing property value or default value is not set: " + key);
        return LONG_CONVERTER.convert(value == null ? defaultVal : value);
    }

    /**
     * Gets the value of a system property as a long.
     * @return system property long value if it exists, defaultValue otherwise.
     */
    public long getLong(long overrideDefaultValue)
    {
        String value = System.getProperty(key);
        if (value == null)
            return overrideDefaultValue;

        return LONG_CONVERTER.convert(value);
    }

    /**
     * Gets the value of a system property as a double.

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Set the system property, e.g. -Dcassandra.sometuning=1024
2. Use getLong(defaultValue) overload instead of the no-arg version
3. Declare a default value when constructing the CassandraRelevantProperties entry
4. Check the property's existence with props.isPresent()/System.getProperty(key) before calling

Example fix

// before
long size = CassandraRelevantProperties.SOME_TUNING.getLong();
// after
long size = CassandraRelevantProperties.SOME_TUNING.getLong(1024L);

String raw = System.getProperty("cassandra.some_tuning");
if (raw == null) throw new IllegalStateException("Set -Dcassandra.some_tuning");

try {
    long v = CassandraRelevantProperties.SOME_TUNING.getLong();
} catch (ConfigurationException e) {
    long v = 1024L; // explicit fallback
}

When it happens

Trigger: Calling props.getLong() on a CassandraRelevantProperties entry created without a default and without -Dkey=value set in the JVM.

Common situations: Tests or tools reading new tuning properties not set in cassandra-env.sh, code added a property without a default then a caller used the no-default getter, unit tests starting Cassandra in-process with stripped system properties.

Understand the failure class

Background: "missing required config value" errors: why libraries refuse to start when a configuration key is empty, unset, or blank — this error's family across 48 libraries.

Related errors

• Bad value for system property -D%s.Please use a value betwee
• Invalid value for system propery '%s': expected one of %s (c
• Invalid value for system property: expected integer value bu
• Invalid value for system property: expected long value but g
• Invalid value for system property: expected size in bytes wi

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/cca61bc3e8bec4c8. Report an issue: GitHub.