{"record":{"id":"91d2fb2822381968","repo":"apache/hadoop","slug":"readahead-buffers-cannot-have-non-zero-buffer-offs","errorCode":null,"errorMessage":"readahead buffers cannot have non-zero buffer offsets","messagePattern":"readahead buffers cannot have non-zero buffer offsets","errorType":"validation","errorClass":"IllegalArgumentException","httpStatus":null,"severity":"error","filePath":"hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsInputStream.java","lineNumber":551,"sourceCode":"    return bytesToRead;\n  }\n\n  /**\n   * Internal read method which handles read-ahead logic.\n   * @param position to read from\n   * @param b buffer\n   * @param offset in buffer\n   * @param length to read\n   * @param bypassReadAhead whether to bypass read-ahead\n   * @return number of bytes read\n   * @throws IOException if there is an error\n   */\n  protected int readInternal(final long position, final byte[] b, final int offset, final int length,\n                           final boolean bypassReadAhead) throws IOException {\n    if (isReadAheadEnabled() && !bypassReadAhead) {\n      // try reading from read-ahead\n      if (offset != 0) {\n        throw new IllegalArgumentException(\"readahead buffers cannot have non-zero buffer offsets\");\n      }\n      int receivedBytes;\n\n      // queue read-aheads\n      int numReadAheads = this.readAheadQueueDepth;\n      long nextOffset = position;\n      // First read to queue needs to be of readBufferSize and later\n      // of readAhead Block size\n      long nextSize = min((long) bufferSize, contentLength - nextOffset);\n      LOG.debug(\"read ahead enabled issuing readheads num = {}\", numReadAheads);\n      TracingContext readAheadTracingContext = new TracingContext(tracingContext);\n      readAheadTracingContext.setPrimaryRequestID();\n      readAheadTracingContext.setReadType(ReadType.PREFETCH_READ);\n      while (numReadAheads > 0 && nextOffset < contentLength) {\n        LOG.debug(\"issuing read ahead requestedOffset = {} requested size {}\",\n            nextOffset, nextSize);\n        getReadBufferManager().queueReadAhead(this, nextOffset, (int) nextSize,\n                new TracingContext(readAheadTracingContext));","sourceCodeStart":533,"sourceCodeEnd":569,"githubUrl":"https://github.com/apache/hadoop/blob/2add9630210752f88ceb1bb74eb65e37bf41da8e/hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsInputStream.java#L533-L569","documentation":"Error \"readahead buffers cannot have non-zero buffer offsets\" thrown in apache/hadoop.","triggerScenarios":"Read-ahead buffers are submitted with non-zero buffer offsets, violating an internal ABFS invariant.","commonSituations":"See trigger scenarios.","solutions":["This is an internal invariant violation; upgrade hadoop-azure to a version with the fix and report with logs if it persists.","Avoid custom read-ahead configurations that alter buffer handling."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"2add9630210752f88ceb1bb74eb65e37bf41da8e","analyzedAt":"2026-08-22T19:55:07.957Z","schemaVersion":2},"datasetVersion":"2026-08-23T01:17:44.959Z"}