apache/cassandra · error · ConfigurationException

sstable_size_in_mb= is too large; resulting bytes exceed…

Error message

sstable_size_in_mb=%d is too large; resulting bytes exceed Long.MAX_VALUE (%d)

What it means

When computing maxSSTableSizeInBytes = ssSize * 1024 * 1024 with Math.multiplyExact, an oversized sstable_size_in_mb overflows a long and throws ArithmeticException, which LCS converts to this ConfigurationException indicating the configured sstable size exceeds what can be represented.

Solutions

1. Set sstable_size_in_mb to a realistic positive value well below the overflow threshold (e.g. 160)
2. ALTER the table with corrected options
3. Bound-check generated values before applying schema changes

Example fix

// before
{'class':'LeveledCompactionStrategy','sstable_size_in_mb':'99999999999999'}
// after
{'class':'LeveledCompactionStrategy','sstable_size_in_mb':'160'}

long ssSize = Long.parseLong(opts.getOrDefault("sstable_size_in_mb", "160"));
if (ssSize > Long.MAX_VALUE / (1024L * 1024L)) throw new IllegalArgumentException("sstable_size_in_mb too large: " + ssSize);

try { execute(alterStmt); }
catch (ConfigurationException e) { if (e.getMessage().contains("exceed Long.MAX_VALUE")) { /* reset sstable_size_in_mb to sane value */ } else throw e; }

When it happens

Trigger: sstable_size_in_mb greater than Long.MAX_VALUE/1048576 (about 8.8e12 MB) supplied in compaction options.

Common situations: Fat-fingered config values with many extra digits; automated config generation bugs multiplying values.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• At most bytes may be in a compaction level; your…
• Cannot set concurrent_validations greater than…
• compaction_throughput: is too large; it should be less than…
• concurrent_compactors should be strictly greater than 0…
• Could not set new local compaction strategy

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/d00dbd6e7ace362b. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/db/compaction/LeveledCompactionStrategy.java:641

        catch (NumberFormatException ex)
        {
            throw new ConfigurationException(String.format("%s is not a parsable int (base10) for %s", levelFanoutSize, LEVEL_FANOUT_SIZE_OPTION), ex);
        }

        // Validate max Bytes for a level
        try
        {
            long maxSSTableSizeInBytes = Math.multiplyExact(ssSize, 1024L * 1024L); // Convert MB to Bytes
            BigInteger fanoutPower = BigInteger.valueOf(fanoutSize).pow(MAX_LEVEL_COUNT - 1);
            BigInteger maxBytes = fanoutPower.multiply(BigInteger.valueOf(maxSSTableSizeInBytes));
            BigInteger longMaxValue = BigInteger.valueOf(Long.MAX_VALUE);
            if (maxBytes.compareTo(longMaxValue) > 0)
                throw new ConfigurationException(String.format("At most %s bytes may be in a compaction level; " +
                        "your maxSSTableSize must be absurdly high to compute %s", Long.MAX_VALUE, maxBytes));
        }
        catch (ArithmeticException ex)
        {
            throw new ConfigurationException(String.format("sstable_size_in_mb=%d is too large; resulting bytes exceed Long.MAX_VALUE (%d)", ssSize, Long.MAX_VALUE), ex);
        }

        uncheckedOptions.remove(LEVEL_FANOUT_SIZE_OPTION);
        uncheckedOptions.remove(SINGLE_SSTABLE_UPLEVEL_OPTION);

        uncheckedOptions.remove(CompactionParams.Option.MIN_THRESHOLD.toString());
        uncheckedOptions.remove(CompactionParams.Option.MAX_THRESHOLD.toString());

        uncheckedOptions = SizeTieredCompactionStrategyOptions.validateOptions(options, uncheckedOptions);

        return uncheckedOptions;
    }
}

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