code: func (db *MemDB) initialize() error {
  	root := db.getRoot()
  	for tName, tableSchema := range db.schema.Tables {
  		for iName := range tableSchema.Indexes {
  			index := iradix.New()
  			path := indexPath(tName, iName)
  			root, _, _ = root.Insert(path, index)
  		}
  	}
  	db.root = unsafe.Pointer(root)
  	return nil
  }
docs: // initialize is used to setup the DB for use after creation. This should
  // be called only once after allocating a MemDB.