For a given query, we filter the whole graph through the index to get a smaller candidate set.Thus, high time-complexity subgraph isomorphism matching operations are reduced. 对于给定的查询，我们使用这些索引过滤图数据库，得到较小的候选集，减少需要进行的高时间复杂度的子图同构匹配。
In the second phase, we search the index and extract those candidate blocks whose distance to the feature vector of the query sequence is less than a predefined threshold. 在第二阶段中，我们搜寻整个索引，找出与待查询序列的特徵向量之间的距离小于某个门槛值的候选子序列。
