apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/service/InstanceService.java/InstanceService/findInstanceConfigsByNamespaceWithReleaseKeysNotIn
class InstanceService:  public List<InstanceConfig> findInstanceConfigsByNamespaceWithReleaseKeysNotIn(String appId,
                                                                                 String clusterName,
                                                                                 String
                                                                                     namespaceName,
                                                                                 Set<String>
                                                                                     releaseKeysNotIn) {
    List<InstanceConfig> instanceConfigs = instanceConfigRepository.
        findByConfigAppIdAndConfigClusterNameAndConfigNamespaceNameAndDataChangeLastModifiedTimeAfterAndReleaseKeyNotIn(appId, clusterName,
            namespaceName, getValidInstanceConfigDate(), releaseKeysNotIn);

    if (CollectionUtils.isEmpty(instanceConfigs)) {
      return Collections.emptyList();
    }

    return instanceConfigs;
  }