Question

我搜索了一下我的问题，但找不到解决方案。

我运行PostgreSQL 9.2.4 on x86_64-unknown-linux-gnu, compiled by gcc (Debian 4.7.2-5) 4.7.2, 64-bit，我的查询非常简单。

EXPLAIN (ANALYZE) SELECT CUSTOMER, PRICE, BUYDATE FROM dbo.Invoice WHERE CUSTOMER = 11111111 AND BUYDATE BETWEEN '2012-11-01' AND '2013-10-31';

输出：

                                                                       QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------
 Bitmap Heap Scan on Invoice  (cost=88193.54..152981.03 rows=20699 width=14) (actual time=987.205..987.242 rows=36 loops=1)
   Recheck Cond: ((CUSTOMER = 11111111) AND (BUYDATE >= '2012-11-01'::date) AND (BUYDATE <= '2013-10-31'::date))
   ->  BitmapAnd  (cost=88193.54..88193.54 rows=20699 width=0) (actual time=987.189..987.189 rows=0 loops=1)
         ->  Bitmap Index Scan on ix_Invoice  (cost=0.00..1375.69 rows=74375 width=0) (actual time=0.043..0.043 rows=40 loops=1)
               Index Cond: (CUSTOMER = 11111111)
         ->  Bitmap Index Scan on ix_Invoice3  (cost=0.00..86807.24 rows=4139736 width=0) (actual time=986.562..986.562 rows=4153999 loops=1)
               Index Cond: ((BUYDATE >= '2012-11-01'::date) AND (BUYDATE <= '2013-10-31'::date))
 Total runtime: 987.294 ms
(8 rows)

表格结构：

      Column      |           Type            | Modifiers | Storage  | Stats target | Description
-----------------+---------------------------+-----------+----------+--------------+-------------
 profitcenter    | character varying(5)      | not null  | extended |              |
 invoicenumber   | character varying(10)     | not null  | extended |              |
 invoiceposition | character varying(6)      | not null  | extended |              |
 buydate         | date                      | not null  | plain    |              |
 customer        | integer                   |           | plain    |              |
 nettowert       | numeric(18,2)             |           | main     |              |
Indexes:
    "filialbons_key" PRIMARY KEY, btree (profitcenter, invoicenumber, invoiceposition, buydate)
    "ix_Invoice" btree (customer)
    "ix_Invoice2" btree (invoicenumber)
    "ix_Invoice3" btree (buydate)
    "ix_Invoice4" btree (articlenumber)
Has OIDs: no

查询的输出示例：

customer | price | buydate
--------------+-----------+----
 11111111 |  8.32 | 2013-02-06
 11111111 |  5.82 | 2013-02-06
 11111111 | 16.64 | 2013-02-06

我在MSSQL 2010上运行了相同的查询？将Date列表示为varchar（）并且速度更快。

感谢您的帮助

Answer 1

索引（customer，buydate）查询应该更快。
您可以尝试通过收集更多统计数据来帮助规划人员选择更好的计划：

ALTER TABLE Invoice ALTER COLUMN customer SET STATISTICS 1000;
ALTER TABLE Invoice ALTER COLUMN buydate SET STATISTICS 1000;
分析发票;

慢速选择DATE之间的查询

1 个答案: