apache/cassandra · error · IOException

Corrupt value length %d encountered, as it exceeds the maxim

Error message

Corrupt value length %d encountered, as it exceeds the maximum of %d, which is set via max_value_size in cassandra.yaml

What it means

During AbstractType.read, a decoded value length exceeding maxValueSize (from max_value_size in cassandra.yaml, default 256MB) is rejected as corrupt with this IOException. It protects against OOM from bogus or malicious length headers.

Source

Thrown at src/java/org/apache/cassandra/db/marshal/AbstractType.java:664

    public byte[] readArray(DataInputPlus in, int maxValueSize) throws IOException
    {
        return read(ByteArrayAccessor.instance, in, maxValueSize);
    }

    public <V> V read(ValueAccessor<V> accessor, DataInputPlus in, int maxValueSize) throws IOException
    {
        int length = valueLengthIfFixed;

        if (length >= 0)
            return accessor.read(in, length);
        else
        {
            int l = in.readUnsignedVInt32();
            if (l < 0)
                throw new IOException("Corrupt (negative) value length encountered");

            if (l > maxValueSize)
                throw new IOException(String.format("Corrupt value length %d encountered, as it exceeds the maximum of %d, " +
                                                    "which is set via max_value_size in cassandra.yaml",
                                                    l, maxValueSize));

            return accessor.read(in, l);
        }
    }

    public void skipValue(DataInputPlus in) throws IOException
    {
        int length = valueLengthIfFixed;
        if (length >= 0)
            in.skipBytesFully(length);
        else
            ByteBufferUtil.skipWithVIntLength(in);
    }

    public final boolean referencesUserType(ByteBuffer name)
    {

View on GitHub (pinned to 88fd0f6a0e)

Solutions

Verify data integrity (nodetool scrub/verify) and repair from replicas; the length is likely corrupt.
If values are legitimately large, raise max_value_size in cassandra.yaml consistently across all nodes and restart.
Check that all nodes in the cluster use the same max_value_size before streaming.

Example fix

# cassandra.yaml — if large values are legitimate
# before
max_value_size: 256
# after (mb)
max_value_size: 512

Defensive patterns

Strategy: validation

Validate before calling

int max = DatabaseDescriptor.getMaxValueSize();
if (declaredLength > max) throw new IllegalArgumentException("value length " + declaredLength + " exceeds max_value_size " + max);

Try / catch

catch (IOException e) { if (e.getMessage().contains("max_value_size")) log.error("value exceeds max_value_size; check cassandra.yaml or data corruption"); throw e; }

Prevention

Keep max_value_size identical on every node before streaming or repair.
Model row values to stay well under the configured limit.
Investigate large-length errors as likely corruption first (scrub/verify), config change second.

When it happens

Trigger: read/readBuffer/readArray on a stream whose VInt length field decodes to a value larger than the configured maxValueSize.

Common situations: Corrupted length bytes in SSTables/commitlog; operator lowered max_value_size while large legacy values exist on disk; streaming data written by a node with a larger max_value_size than the reader.

Understand the failure class

Background: payload too large / request exceeds maximum size: why libraries cap bytes and how to fix oversize payloads — this error's family across 50 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/af0a63b7fbafe215. Report an issue: GitHub.