apache/cassandra · error · IllegalArgumentException

new position should not be negative

Error message

new position should not be negative

What it means

RandomAccessReader.seek(newPosition) validates that the target offset is non-negative before moving the read cursor. Negative offsets cannot exist in a file, so this indicates a caller bug (underflow or bad offset arithmetic) and throws IllegalArgumentException.

Solutions

1. Validate offsets read from files before seeking (reject negatives with a clear corrupt-file error)
2. Clamp: if (off >= 0) seek(off) else throw/handle corruption
3. Fix the offset arithmetic so it cannot underflow (e.g. check minuend >= subtrahend)
4. Run an sstable verify/scrub — a negative offset usually means on-disk corruption

Example fix

// before
long offset = readLongFromFile() - headerSize; // may underflow
reader.seek(offset);
// after
long offset = readLongFromFile() - headerSize;
if (offset < 0)
    throw new CorruptFileException("negative offset " + offset);
reader.seek(offset);

if (offset < 0) throw new CorruptFileException("negative offset: " + offset); reader.seek(offset);

boolean seekable = offset >= 0 && offset <= reader.getLength();

try { reader.seek(offset); } catch (IllegalArgumentException e) { throw new CorruptFileException(e.getMessage()); }

When it happens

Trigger: Calling rar.seek(negativeLong) — commonly from callers like readSyncMarker, keyIterator/keyReader, createReader, reset, or skipBytes when an offset computation underflows (e.g. position - size where size > position) or a corrupted length/offset field is read from disk and used directly.

Common situations: Reading a corrupted or partially-written sstable whose stored offsets are bogus; subtracting a header size from offset 0; using unsigned values read from disk in signed long math.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Unable to seek to position
• Attempted skipBytes() on a closed RAR
• Attempted to seek in a closed RAR
• Length must be positive
• Length must not be negative

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/ebf2a6d7084d971c. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/io/util/RandomAccessReader.java:221

    /**
     * Class to hold a mark to the position of the file
     */
    private static class BufferedRandomAccessFileMark implements DataPosition
    {
        final long pointer;

        private BufferedRandomAccessFileMark(long pointer)
        {
            this.pointer = pointer;
        }
    }

    @Override
    public void seek(long newPosition)
    {
        if (newPosition < 0)
            throw new IllegalArgumentException("new position should not be negative");

        if (buffer == null)
            throw new IllegalStateException("Attempted to seek in a closed RAR");

        long bufferOffset = bufferHolderOffset;
        if (newPosition >= bufferOffset && newPosition < bufferOffset + buffer.limit())
        {
            buffer.position((int) (newPosition - bufferOffset));
            return;
        }

        if (newPosition > length())
            throw new IllegalArgumentException(String.format("Unable to seek to position %d in %s (%d bytes) in read-only mode",
                                                         newPosition, getPath(), length()));
        reBufferAt(newPosition);
    }

    @Override

View on GitHub (pinned to 88fd0f6a0e)