@Override
    public void prePut(ObserverContext<? extends RegionCoprocessorEnvironment> e, Put put,
      WALEdit edit, Durability durability) throws IOException {
      Region region = e.getEnvironment().getRegion();
      if (
        !region.getRegionInfo().isMetaRegion() && !region.getRegionInfo().getTable().isSystemTable()
      ) {
        // The put carries the TTL attribute
        if (put.getTTL() != Long.MAX_VALUE) {
          return;
        }
        throw new IOException("Operation does not have TTL set");
      }
    }
Force use of combiner in doMROnTableTest. Boolean. Default is true.
hbase-mapreduce/src/test/java/org/apache/hadoop/hbase/mapreduce/TestImportTSVWithTTLs.java