code: void removeGlobalUniqueIndex(GlobalUniqueIndex index, boolean preserveData) {
          getTopology().lock();
          String fn = index.getName();
          if (!uncommittedRemovedGlobalUniqueIndexes.contains(fn)) {
              uncommittedRemovedGlobalUniqueIndexes.add(fn);
              TopologyManager.removeGlobalUniqueIndex(sqlgGraph, fn);
              if (!preserveData) {
                  getVertexLabel(index.getName()).ifPresent(
                          (VertexLabel vl) -> vl.remove(false));
              }
              getTopology().fire(index, "", TopologyChangeAction.DELETE);
          }
      }
docs: remove the given global unique index
  
  @param index        the index to remove
  @param preserveData should we keep the sql data?