看下面的截图

postgres=#   explain (analyze,buffers)   select  * from t4 where bh2  = '652e4e0e-ba60-0400-25b5-4ee5e490fffe';                                                           QUERY PLAN                                                           ------------------------------------------------------------------------------------------------------------------------------  Streaming (type: GATHER)  (cost=4.95..51.75 rows=31 width=102) (actual time=2.341..2.597 rows=32 loops=1)    Node/s: All datanodes    (Buffers: shared hit=1)    ->  Bitmap Heap Scan on t4  (cost=4.33..43.75 rows=31 width=102) (actual time=[0.044,0.044]..[0.092,0.228], rows=32)          Recheck Cond: ((bh2)::text = '652e4e0e-ba60-0400-25b5-4ee5e490fffe'::text)          Buffers: shared max hit=36 min hit=3          ->  Bitmap Index Scan on i_t4  (cost=0.00..4.33 rows=31 width=0) (actual time=[0.038,0.038]..[0.059,0.059], rows=32)                Index Cond: ((bh2)::text = '652e4e0e-ba60-0400-25b5-4ee5e490fffe'::text)                Buffers: shared max hit=4 min hit=3  Total runtime: 3.091 ms (10 rows) Time: 7.289 ms postgres=# select * from pg_stat_all_indexes where relname ='t4';    relid  | indexrelid | schemaname | relname | indexrelname | idx_scan | idx_tup_read | idx_tup_fetch  --------+------------+------------+---------+--------------+----------+--------------+---------------  892383 |     894076 | sa         | t4      | i_t4         |        0 |            0 |             0 (1 row) Time: 5.915 ms postgres=# select schemaname,relname,seq_scan,idx_scan from pg_stat_all_tables where relname ='t4';  schemaname | relname | seq_scan | idx_scan  ------------+---------+----------+----------  sa         | t4      |       15 |        0 (1 row) Time: 3.736 ms