Postgres 17

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CREATE TABLE tbl (id INT PRIMARY KEY);
INSERT INTO tbl (id) SELECT * FROM generate_series(0, 100000);

CREATE TABLE

INSERT 0 100001

EXPLAIN ANALYZE
SELECT * FROM tbl WHERE id = 69420;

QUERY PLAN

Index Only Scan using tbl_pkey on tbl  (cost=0.29..8.31 rows=1 width=4) (actual time=0.028..0.029 rows=1 loops=1)

  Index Cond: (id = 69420)

  Heap Fetches: 1

Planning Time: 1.251 ms

Execution Time: 0.066 ms

EXPLAIN

EXPLAIN ANALYZE
SELECT * FROM tbl  WHERE id IN 
  ( SELECT id FROM tbl WHERE id = 69420);

QUERY PLAN

Nested Loop Semi Join  (cost=0.58..16.63 rows=1 width=4) (actual time=0.014..0.016 rows=1 loops=1)

  ->  Index Only Scan using tbl_pkey on tbl  (cost=0.29..8.31 rows=1 width=4) (actual time=0.010..0.011 rows=1 loops=1)

        Index Cond: (id = 69420)

        Heap Fetches: 1

  ->  Index Only Scan using tbl_pkey on tbl tbl_1  (cost=0.29..8.31 rows=1 width=4) (actual time=0.002..0.002 rows=1 loops=1)

        Index Cond: (id = 69420)

        Heap Fetches: 1

Planning Time: 0.585 ms

Execution Time: 0.038 ms

EXPLAIN