core/src/main/java/com/orientechnologies/orient/core/sql/executor/OSelectExecutionPlanner.java
private Set<String> getServersThatHasAllClusters(Map<String, Set<String>> clusterMap, Set<String> queryClusters) {
    Set<String> remainingServers = clusterMap.keySet();
    for (String cluster : queryClusters) {
      for (Map.Entry<String, Set<String>> serverConfig : clusterMap.entrySet()) {
        if (!serverConfig.getValue().contains(cluster)) {
          remainingServers.remove(serverConfig.getKey());
        }
      }
    }
    return remainingServers;
  }
private Set<String> getServersThatHasAllClusters(Map<String, Set<String>> clusterMap, Set<String> queryClusters) {
    Set<String> remainingServers = clusterMap.keySet();
    for (String cluster : queryClusters) {
      for (Map.Entry<String, Set<String>> serverConfig : clusterMap.entrySet()) {
        if (!serverConfig.getValue().contains(cluster)) {
          remainingServers.remove(serverConfig.getKey());
        }
      }
    }
    return remainingServers;
  }
@param clusterMap    the cluster map for current sharding configuration
@param queryClusters the clusters that are target of the query

@return