Partition Seq Scan

名称

分区表顺序扫描算子

介绍

在分区表上对数据进行顺序扫描，类似于普通表的 Seq Scan。

举例

--清理环境
DROP TABLE t1;

--创建分区表
CREATE TABLE t1
(
    id NUMERIC(6) ,
    time_id DATE
)
PARTITION BY RANGE (time_id)
(
    PARTITION p1 VALUES LESS THAN ('2021-01-01'),
    PARTITION p2 VALUES LESS THAN ('2022-01-01')
);

INSERT INTO t1 VALUES(1,'2021-10-01');
ANALYZE t1;

EXPLAIN ANALYZE SELECT * from t1 partition (p2);
                                               QUERY PLAN
--------------------------------------------------------------------------------------------------------
 Partition Seq Scan on TS(2)  (cost=0.00..7.01 rows=1 width=24) (actual time=0.02..0.03 rows=1 loops=1)
 Planning Time: 0.09 msec
 Execution Time: 0.08 msec
(3 rows)

• on TS(2) 表示要扫描的分区