apache/hadoop · error · IllegalArgumentException

readahead buffers cannot have non-zero buffer offsets

Error message

readahead buffers cannot have non-zero buffer offsets

What it means

Error "readahead buffers cannot have non-zero buffer offsets" thrown in apache/hadoop.

Source

Thrown at hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsInputStream.java:551

    return bytesToRead;
  }

  /**
   * Internal read method which handles read-ahead logic.
   * @param position to read from
   * @param b buffer
   * @param offset in buffer
   * @param length to read
   * @param bypassReadAhead whether to bypass read-ahead
   * @return number of bytes read
   * @throws IOException if there is an error
   */
  protected int readInternal(final long position, final byte[] b, final int offset, final int length,
                           final boolean bypassReadAhead) throws IOException {
    if (isReadAheadEnabled() && !bypassReadAhead) {
      // try reading from read-ahead
      if (offset != 0) {
        throw new IllegalArgumentException("readahead buffers cannot have non-zero buffer offsets");
      }
      int receivedBytes;

      // queue read-aheads
      int numReadAheads = this.readAheadQueueDepth;
      long nextOffset = position;
      // First read to queue needs to be of readBufferSize and later
      // of readAhead Block size
      long nextSize = min((long) bufferSize, contentLength - nextOffset);
      LOG.debug("read ahead enabled issuing readheads num = {}", numReadAheads);
      TracingContext readAheadTracingContext = new TracingContext(tracingContext);
      readAheadTracingContext.setPrimaryRequestID();
      readAheadTracingContext.setReadType(ReadType.PREFETCH_READ);
      while (numReadAheads > 0 && nextOffset < contentLength) {
        LOG.debug("issuing read ahead requestedOffset = {} requested size {}",
            nextOffset, nextSize);
        getReadBufferManager().queueReadAhead(this, nextOffset, (int) nextSize,
                new TracingContext(readAheadTracingContext));

View on GitHub (pinned to 2add963021)

Solutions

1. This is an internal invariant violation; upgrade hadoop-azure to a version with the fix and report with logs if it persists.
2. Avoid custom read-ahead configurations that alter buffer handling.

When it happens

Trigger: Read-ahead buffers are submitted with non-zero buffer offsets, violating an internal ABFS invariant.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/91d2fb2822381968. Report an issue: GitHub.