@Override
  public List<Stage> getAllStages(long requestId) {
    List<StageEntity> stageEntities = stageDAO.findByRequestId(requestId);
    List<Stage> stages = new ArrayList<>(stageEntities.size());
    for (StageEntity stageEntity : stageEntities ){
      stages.add(stageFactory.createExisting(stageEntity));
    }

    return stages;
  }
Cache for auditlog. It stores a {@link RequestDetails} object for every requests.
{@link RequestDetails} contains the previous status of the request and a map for tasks.
A task has a {@link RequestDetails.Component} key and the value of that is the previous status of the task.
{@link RequestDetails.Component} contains the component name and the host name
ambari-server/src/main/java/org/apache/ambari/server/actionmanager/ActionDBAccessorImpl.java