code: void removeIndex(Index idx, boolean preserveData) {
          this.getSchema().getTopology().lock();
          if (!uncommittedRemovedIndexes.contains(idx.getName())) {
              uncommittedRemovedIndexes.add(idx.getName());
              TopologyManager.removeIndex(this.sqlgGraph, idx);
              if (!preserveData) {
                  idx.delete(sqlgGraph);
              }
              this.getSchema().getTopology().fire(idx, "", TopologyChangeAction.DELETE);
          }
      }
docs: remove a given index that was on this label
  
  @param idx          the index
  @param preserveData should we keep the SQL data