@Override
  public AbortCompactResponse abortCompactions(AbortCompactionRequest reqst) throws MetaException, NoSuchCompactionException {
    if (reqst.getCompactionIds().isEmpty()) {
      LOG.info("Compaction ids are missing in request. No compactions to abort");
      throw new NoSuchCompactionException("Compaction ids missing in request. No compactions to abort");
    }
    return new AbortCompactionFunction(reqst, sqlRetryHandler).execute(jdbcResource);    
  }
Isolation Level Notes
Plain: RC is OK
This will find transactions that have timed out and abort them.
Will also delete locks which are not associated with a transaction and have timed out
Tries to keep transactions (against metastore db) small to reduce lock contention.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java