小编Kej*_*jlo的帖子

我总是了解到并理解，只有当我们对前导（或所有）列有谓词时才能使用索引。现在，令我惊讶的是，我注意到以下查询中使用了GiST 索引。这是为什么？这是 GiST 索引的特殊功能吗？

CREATE TABLE t1 (
    i INT, 
    j INT, 
    k INT
);

INSERT INTO t1 
SELECT i, j, k 
FROM   GENERATE_SERIES(1, 100) AS i, 
       GENERATE_SERIES(1, 100) AS j, 
       GENERATE_SERIES(1, 100) AS k;

CREATE INDEX ON t1 USING GiST(i, j, k);

EXPLAIN SELECT * FROM t1 WHERE k = 54;

QUERY PLAN
Bitmap Heap Scan on t1  (cost=199.03..5780.51 rows=5000 width=12)
  Recheck Cond: (k = 54)
  ->  Bitmap Index Scan on t1_i_j_k_idx  (cost=0.00..197.78 rows=5000 width=0)
        Index Cond: …