private static long getTotalKvCount(final Collection<HStoreFile> candidates) {
    long totalSize = 0;
    for (HStoreFile storeFile : candidates) {
      totalSize += storeFile.getReader().getEntries();
    }
    return totalSize;
  }
Selects the compaction of a single stripe using default policy.
@param sfs          Files.
@param allFilesOnly Whether a compaction of all-or-none files is needed.
@return The resulting selection.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/compactions/StripeCompactionPolicy.java