What causes "%s must be non negative: %d" in apache/cassandra?

Set min_sstable_size to a non-negative byte value (e.g. '52428800' for 50MB) or remove it to use the default (50MB).

apache/cassandra · error · ConfigurationException

%s must be non negative: %d

Error message

%s must be non negative: %d

What it means

ConfigurationException thrown by SizeTieredCompactionStrategyOptions.validateOptions when the min_sstable_size option parses as a valid long but is negative. Minimum SSTable size for size-tiered bucketing must be >= 0, so a negative value is rejected before the strategy is instantiated.

Source

Thrown at src/java/org/apache/cassandra/db/compaction/SizeTieredCompactionStrategyOptions.java:75

        try
        {
            return optionValue == null ? defaultValue : Double.parseDouble(optionValue);
        }
        catch (NumberFormatException e)
        {
            throw new ConfigurationException(String.format("%s is not a parsable float for %s", optionValue, key), e);
        }
    }

    public static Map<String, String> validateOptions(Map<String, String> options, Map<String, String> uncheckedOptions) throws ConfigurationException
    {
        String optionValue = options.get(MIN_SSTABLE_SIZE_KEY);
        try
        {
            long minSSTableSize = optionValue == null ? DEFAULT_MIN_SSTABLE_SIZE : Long.parseLong(optionValue);
            if (minSSTableSize < 0)
            {
                throw new ConfigurationException(String.format("%s must be non negative: %d", MIN_SSTABLE_SIZE_KEY, minSSTableSize));
            }
        }
        catch (NumberFormatException e)
        {
            throw new ConfigurationException(String.format("%s is not a parsable int (base10) for %s", optionValue, MIN_SSTABLE_SIZE_KEY), e);
        }

        double bucketLow = parseDouble(options, BUCKET_LOW_KEY, DEFAULT_BUCKET_LOW);
        double bucketHigh = parseDouble(options, BUCKET_HIGH_KEY, DEFAULT_BUCKET_HIGH);
        if (bucketHigh <= bucketLow)
        {
            throw new ConfigurationException(String.format("%s value (%s) is less than or equal to the %s value (%s)",
                                                           BUCKET_HIGH_KEY, bucketHigh, BUCKET_LOW_KEY, bucketLow));
        }

        uncheckedOptions.remove(MIN_SSTABLE_SIZE_KEY);
        uncheckedOptions.remove(BUCKET_LOW_KEY);
        uncheckedOptions.remove(BUCKET_HIGH_KEY);

View on GitHub (pinned to 88fd0f6a0e)

Solutions

Set min_sstable_size to a non-negative byte value (e.g. '52428800' for 50MB) or remove it to use the default (50MB).
Re-run ALTER TABLE with the corrected compaction map.
Add caller-side validation rejecting negative byte sizes before applying schema options.

Example fix

// before
{'class':'SizeTieredCompactionStrategy','min_sstable_size':'-1024'}
// after
{'class':'SizeTieredCompactionStrategy','min_sstable_size':'52428800'}

Defensive patterns

Strategy: validation

Validate before calling

long minSstableSize = Long.parseLong(opts.getOrDefault("min_sstable_size", "52428800"));
if (minSstableSize < 0) throw new IllegalArgumentException("min_sstable_size must be >= 0");

Try / catch

try { schema.alterTable(cql); } catch (ConfigurationException e) { if (e.getMessage().contains("must be non negative")) { /* fix the option and retry */ } else throw e; }

Prevention

Never emit negative byte sizes; clamp with Math.max(0, size).
Sanitize option values for stray '-' signs before building the compaction map.
Keep sizes as plain decimal byte strings in templates.

When it happens

Trigger: CREATE/ALTER TABLE with compaction option {'min_sstable_size': '-1024'} — any value < 0 supplied for min_sstable_size on SizeTieredCompactionStrategy.

Common situations: Hand-edited schema options where a '-' was typed accidentally; a sizing tool writing negative bytes after a failed computation; copy-paste of a value intended for another option.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/051dbfd85bea7571. Report an issue: GitHub.