apache/cassandra · error · ConfigurationException

is not a valid number between 0 and 1

Error message

%s is not a valid number between 0 and 1: %s

What it means

The unified compaction controller validates the 'sstable_growth' option by parsing it with FBUtilities.parsePercent. If the string is not a valid number/percentage at all (e.g. 'high', '0,5'), the resulting NumberFormatException is rethrown as a ConfigurationException identifying the option.

Solutions

1. Set sstable_growth to a valid numeric value between 0 and 1, e.g. '0.3' or '30%'.
2. Use a dot as the decimal separator, not a comma.
3. Remove the option to fall back to the default.
4. Inspect the cause's message (e.getMessage()) for the exact parse failure.

Example fix

// before
compaction = {'class': 'UnifiedCompactionStrategy', 'sstable_growth': '0,3'};
// after
compaction = {'class': 'UnifiedCompactionStrategy', 'sstable_growth': '0.3'};

String v = options.get("sstable_growth");
if (v != null) {
    try { Double.parseDouble(v.replace("%", "")); }
    catch (NumberFormatException e) { throw new IllegalArgumentException("sstable_growth must be numeric: " + v); }
}

try { strategy.validateOptions(opts); } catch (ConfigurationException e) { logger.error("Unparseable sstable_growth: {}", e.getMessage()); }

When it happens

Trigger: Calling validateOptions with an sstable_growth value that cannot be parsed as a number or percentage, such as 'fast' or '0,5' with a comma decimal separator.

Common situations: Free-text config values, comma-vs-dot decimal locale mistakes, truncation by templating tools, or editing the option by hand.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• concurrent_compactors should be strictly greater than 0…
• Could not set new local compaction strategy
• Disabling compaction by setting compaction thresholds to 0…
• Fan factor cannot be lower than 2 in
• Invalid configuration

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/4e61c173090bd873. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/db/compaction/unified/Controller.java:662

            }
        }

        s = options.remove(SSTABLE_GROWTH_OPTION);
        if (s != null)
        {
            try
            {
                double targetSSTableGrowth  = FBUtilities.parsePercent(s);
                if (targetSSTableGrowth < 0 || targetSSTableGrowth > 1)
                {
                    throw new ConfigurationException(String.format("%s %s must be between 0 and 1",
                                                                   SSTABLE_GROWTH_OPTION,
                                                                   s));
                }
            }
            catch (NumberFormatException e)
            {
                throw new ConfigurationException(String.format("%s is not a valid number between 0 and 1: %s",
                                                               SSTABLE_GROWTH_OPTION,
                                                               e.getMessage()),
                                                 e);
            }
        }

        return options;
    }

    private static void validateBoolean(Map<String, String> options, String option)
    {
        String s;
        s = options.remove(option);
        if (s != null && !s.equalsIgnoreCase("true") && !s.equalsIgnoreCase("false")) {
            throw new ConfigurationException(String.format("%s should either be 'true' or 'false', not %s",
                    option, s));
        }
    }

View on GitHub (pinned to 88fd0f6a0e)