public OperationStatus[] batchMutate(Mutation[] mutations, boolean atomic, long nonceGroup,
    long nonce) throws IOException {
    // As it stands, this is used for 3 things
    // * batchMutate with single mutation - put/delete/increment/append, separate or from
    // checkAndMutate.
    // * coprocessor calls (see ex. BulkDeleteEndpoint).
    // So nonces are not really ever used by HBase. They could be by coprocs, and checkAnd...
    return batchMutate(new MutationBatchOperation(this, mutations, atomic, nonceGroup, nonce));
  }
During replay, there could exist column families which are removed between region server
failure and replay
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java