private synchronized void setMergeDocStoreIsCompoundFile(MergePolicy.OneMerge merge) {
    final String mergeDocStoreSegment = merge.info.getDocStoreSegment(); 
    if (mergeDocStoreSegment != null && !merge.info.getDocStoreIsCompoundFile()) {
      final int size = segmentInfos.size();
      for(int i=0;i<size;i++) {
        final SegmentInfo info = segmentInfos.info(i);
        final String docStoreSegment = info.getDocStoreSegment();
        if (docStoreSegment != null &&
            docStoreSegment.equals(mergeDocStoreSegment) && 
            info.getDocStoreIsCompoundFile()) {
          merge.info.setDocStoreIsCompoundFile(true);
          break;
        }
      }
    }
  }