private void clearRow(int fileId) throws IOException {
    long offsetInFile = toOffsetInFile(fileId);
    int offsetInPage = storage.toOffsetInPage(offsetInFile);

    Page page = storage.pageByOffset(offsetInFile);
    ByteBuffer rawPageBuffer = page.rawPageBuffer();

    rawPageBuffer.put(offsetInPage, rowOfZeroes);//plain write, not volatile!
  }
private void clearRow(int fileId)