protected boolean nextBlock(int readIntoOffset) throws HiveException {
    itrCursor = 0;
    this.readBlockSize = 0;
    if (this.numFlushedBlocks == 0) {
      return false;
    }

    try {
      if (val == null) {
        val = serde.getSerializedClass().newInstance();
      }
      boolean nextSplit = true;
      int i = readIntoOffset;

      if (rr != null) {
        Object key = rr.createKey();
        while (i < this.currentReadBlock.length && rr.next(key, val)) {
          nextSplit = false;
          this.currentReadBlock[i++] = (ROW) ObjectInspectorUtils.copyToStandardObject(serde
              .deserialize(val), serde.getObjectInspector(), ObjectInspectorCopyOption.WRITABLE);
        }
      }

      if (nextSplit && this.currentSplitPointer < this.actualSplitNum) {
        JobConf localJc = getLocalFSJobConfClone(jc);
        // open record reader to read next split
        rr = inputFormat.getRecordReader(inputSplits[currentSplitPointer], jobCloneUsingLocalFs,
            reporter);
        currentSplitPointer++;
        return nextBlock(0);
      }

      this.readBlockSize = i;
      return this.readBlockSize > 0;
    } catch (Exception e) {
      LOG.error(e.getMessage(), e);
      try {
        this.clearRows();
      } catch (HiveException e1) {
        LOG.error(e.getMessage(), e);
      }
      throw new HiveException(e);
    }
  }
Get the number of elements in the RowContainer.

@return number of elements in the RowContainer
ql/src/java/org/apache/hadoop/hive/ql/exec/persistence/RowContainer.java