postgresql - PostgreSQL 哈希索引的时间复杂度是多少？

Question

我猜创建哈希索引是 O(n)，而用它来访问数据也得到 O(n)，所以，它比 b-tree 索引更好？

Answer 1

来自manual :

Note: Testing has shown PostgreSQL's hash indexes to perform no better than B-tree indexes, and the index size and build time for hash indexes is much worse. Furthermore, hash index operations are not presently WAL-logged, so hash indexes might need to be rebuilt with REINDEX after a database crash. For these reasons, hash index use is presently discouraged.

手册的后续版本不再提及性能问题，只关注复制问题。

看起来使用哈希索引没有意义。