apache/cassandra · error · ConfigurationException

Compression parameters too long, length

Error message

Compression parameters too long, length %d cannot be above 65535.

What it means

CommitLogDescriptor.writeHeader serializes the segment's compression/encryption parameters as a UTF-8 string, whose length is written as an unsigned short (max 65535 bytes). If the parameters string exceeds that, a ConfigurationException is thrown so the header is never written in a form that could not be read back.

Solutions

Trim the compression/encryption parameter map in cassandra.yaml (or the CompressionParams/EncryptionContext built programmatically) to a sane size.
Remove duplicate or obsolete keys from compression_options / encryption_options.
If building descriptors in tests, generate fewer additionalHeaders so the serialized string stays under 65535 bytes.
Shorten long custom parameter values (e.g. long keystore paths or embedded config blobs).

Example fix

// before
Map<String,String> opts = hugeGeneratedOptionMap; // thousands of entries -> ConfigurationException
// after
Map<String,String> opts = Map.of("class_name", "LZ4Compressor", "chunk_length_in_kb", "16");

Defensive patterns

Strategy: validation

Validate before calling

String s = descriptor.parametersAsCreateString(); // or serialize yourself
if (s.getBytes(StandardCharsets.UTF_8).length > 65535)
    throw new IllegalArgumentException("Compression/encryption parameters too long for commit log header");

Try / catch

try (CommitLogSegmentFile f = open(descriptor)) { ... } catch (ConfigurationException e) { logger.error("Header params too large: {}", e.getMessage()); }

Prevention

Keep compression_options small and explicit
Do not inject large blob-like values into compression/encryption config
Review generated test descriptors for oversized additional headers

When it happens

Trigger: Opening a new commit log segment (writeHeader, via writeHeader-fromHeader path) with a descriptor whose combined compression + encryption + additionalHeaders parameters string exceeds 65535 UTF-8 bytes — typically thousands of compression option entries.

Common situations: cassandra.yaml compression or encryption_context options bloated with very large maps (e.g. many chunk_length/iv parameters or an enormous parameter map injected programmatically in tests).

Understand the failure class

Background: "File too large" / "file size exceeds limit" errors: why libraries cap file sizes and how to fix them — this error's family across 46 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/f886e3825b8e38a9. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/db/commitlog/CommitLogDescriptor.java:112

    {
        writeHeader(out, descriptor, Collections.<String, String>emptyMap());
    }

    /**
     * @param additionalHeaders Allow segments to pass custom header data
     */
    public static void writeHeader(ByteBuffer out, CommitLogDescriptor descriptor, Map<String, String> additionalHeaders)
    {
        CRC32 crc = new CRC32();
        out.putInt(descriptor.version);
        updateChecksumInt(crc, descriptor.version);
        out.putLong(descriptor.id);
        updateChecksumInt(crc, (int) (descriptor.id & 0xFFFFFFFFL));
        updateChecksumInt(crc, (int) (descriptor.id >>> 32));
        String parametersString = constructParametersString(descriptor.compression, descriptor.encryptionContext, additionalHeaders);
        byte[] parametersBytes = parametersString.getBytes(StandardCharsets.UTF_8);
        if (parametersBytes.length != (((short) parametersBytes.length) & 0xFFFF))
            throw new ConfigurationException(String.format("Compression parameters too long, length %d cannot be above 65535.",
                        parametersBytes.length));
        out.putShort((short) parametersBytes.length);
        updateChecksumInt(crc, parametersBytes.length);
        out.put(parametersBytes);
        crc.update(parametersBytes, 0, parametersBytes.length);
        out.putInt((int) crc.getValue());
    }

    @VisibleForTesting
    static String constructParametersString(ParameterizedClass compression, EncryptionContext encryptionContext, Map<String, String> additionalHeaders)
    {
        Map<String, Object> params = new TreeMap<>();
        if (compression != null)
        {
            params.put(COMPRESSION_PARAMETERS_KEY, compression.parameters);
            params.put(COMPRESSION_CLASS_KEY, compression.class_name);
        }
        if (encryptionContext != null)

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