public FlushResultImpl flushcache(boolean flushAllStores, boolean writeFlushRequestWalMarker,
    FlushLifeCycleTracker tracker) throws IOException {
    List<byte[]> families = null;
    if (flushAllStores) {
      families = new ArrayList<>();
      families.addAll(this.getTableDescriptor().getColumnFamilyNames());
    }
    return this.flushcache(families, writeFlushRequestWalMarker, tracker);
  }
Returns True if the flush requested a compaction, else false
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java