apache/flink · error · KryoException

No more bytes left.

Error message

No more bytes left.

What it means

KryoException wrapping EOFException, thrown by NoFetchingInput.readBytes when the underlying stream returns -1 before 'count' bytes have been read. It signals a truncated payload: the reader expected more bytes than the stream contains.

Source

Thrown at flink-core/src/main/java/org/apache/flink/api/java/typeutils/runtime/NoFetchingInput.java:151

    @Override
    public void readBytes(byte[] bytes, int offset, int count) throws KryoException {
        if (bytes == null) {
            throw new IllegalArgumentException("bytes cannot be null.");
        }

        if (count == 0) {
            return;
        }

        try {
            int bytesRead = 0;
            int c;

            while (true) {
                c = inputStream.read(bytes, offset + bytesRead, count - bytesRead);

                if (c == -1) {
                    throw new KryoException(new EOFException("No more bytes left."));
                }

                bytesRead += c;

                if (bytesRead == count) {
                    break;
                }
            }
        } catch (IOException ex) {
            throw new KryoException(ex);
        }
    }
}

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Confirm serializer schema symmetry: the reader must read field lengths exactly as the writer wrote them
2. Validate the stream/framing integrity before deserialization (lengths, checksums)
3. If this occurs on state restore, test restore against the exact checkpoint that produced the data and check for partial uploads

try {
    input.readBytes(buf, 0, len);
} catch (KryoException e) {
    if (e.getCause() instanceof EOFException) {
        throw new IOException("Truncated payload: expected " + len + " bytes", e);
    }
    throw e;
}

When it happens

Trigger: Bulk readBytes(bytes, offset, count) where the serialized data ends early - e.g. a byte[]/String field whose stored length exceeds the remaining stream, or a cut-off stream mid-field.

Common situations: Corrupted or truncated checkpoints/savepoints; a length field written incorrectly (stale length after a field was resized); deserializing with a mismatched schema that reads a longer array length than was written.

Related errors

• Buffer underflow.
• Reached the end of the collection. This could be caused by i
• Failed to serialize value '{value}'
• Cannot register null class or serializer.
• Could not instantiate record

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/a1586f2c764b570d. Report an issue: GitHub.