public Set<InternalDistributedMember> adviseFixedPartitionDataStores(final String partitionName) {
    Set<InternalDistributedMember> s = adviseFilter(profile -> {
      // probably not needed as all profiles for a partitioned region are
      // Partition profiles
      if (profile instanceof PartitionProfile) {
        PartitionProfile p = (PartitionProfile) profile;
        if (p.fixedPAttrs != null) {
          for (FixedPartitionAttributesImpl fpa : p.fixedPAttrs) {
            if (fpa.getPartitionName().equals(partitionName)) {
              return true;
            }
          }
        }
      }
      return false;
    });

    if (s == Collections.EMPTY_SET) {
      s = new HashSet<>();
    }

    if (logger.isTraceEnabled(LogMarker.DISTRIBUTION_ADVISOR_VERBOSE)) {
      logger.trace(LogMarker.DISTRIBUTION_ADVISOR_VERBOSE,
          "adviseFixedPartitionDataStore returning {} from {}", s, toStringWithProfiles());
    }
    return s;
  }
return the set of the distributed members on which the given partition name is defined.
geode-core/src/main/java/org/apache/geode/internal/cache/partitioned/RegionAdvisor.java