protected long getSizeToCheck(final int tableRegionsCount) {
    // safety check for 100 to avoid numerical overflow in extreme cases
    return tableRegionsCount == 0 || tableRegionsCount > 100
      ? getDesiredMaxFileSize()
      : Math.min(getDesiredMaxFileSize(),
        initialSize * tableRegionsCount * tableRegionsCount * tableRegionsCount);
  }
@return Region max size or {@code count of regions cubed * 2 * flushsize}, which ever is
        smaller; guard against there being zero regions on this server.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/IncreasingToUpperBoundRegionSplitPolicy.java