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我有一个包含大约 750 万条记录的表，并且正在尝试基于所述表实现自动完成表单，但性能非常糟糕。

架构（省略无关字段）如下：

COMPANIES
---------
sid (integer primary key)
world_hq_sid (integer)
name (varchar(64))
marketing_alias (varchar(64))
address_country_code (char(4))
address_state (varchar(64))
sort_order integer
search_weight integer
annual_sales integer

传入的字段是可选的 country_code 和 state，以及搜索词。我想要的是搜索词匹配（不区分大小写）名称或marketing_alias 的开头。我想要前十名的结果，那些结果也匹配顶部的国家和州，然后只有国家，然后没有州/国家匹配。之后，我希望结果按 sort_order 排序。

另外，我只想要每个 world_hq_sid 一场比赛。最后，当我得到每个 world_hq_sid 的最佳匹配时，我希望最终结果按 search_weight 排序。

我正在使用窗口查询来实现 world_hq_sid 部分。这是查询：

SELECT * FROM (
    SELECT ROW_NUMBER() OVER (PARTITION BY world_hq_sid ORDER BY CASE WHEN address_country_code = 'US' AND address_state = 'CA' THEN 2 WHEN address_country_code = 'US' THEN 1 ELSE 0 END desc, sort_order asc) AS r,
    companies.*
    FROM companies
    WHERE ((upper(name) LIKE upper('co%')) OR (upper(marketing_alias) LIKE upper('co%')))
  ) x
  WHERE x.r = 1
  ORDER BY CASE WHEN address_country_code = 'US' AND address_state = 'CA' THEN 2 WHEN address_state = 'CA' THEN 1 ELSE 0 END desc, search_weight asc, annual_sales desc
  LIMIT 10;

我在 address_state、address_country_code、world_hq_sid、sort_order 和 search_weight 上有正常的 btree 索引。

我在 name 和 marketing_alias 字段上有以下索引：

CREATE INDEX companies_alias_pattern_upper_idx ON companies(upper(marketing_alias) varchar_pattern_ops);
CREATE INDEX companies_name_pattern_upper_idx ON companies(upper(name) varchar_pattern_ops)

这是当我将 CA 作为状态并将“co”作为搜索词传递时的解释分析

Limit  (cost=676523.01..676523.03 rows=10 width=939) (actual time=18695.686..18695.687 rows=10 loops=1)
 ->  Sort  (cost=676523.01..676526.67 rows=1466 width=939) (actual time=18695.686..18695.687 rows=10 loops=1)
     Sort Key: x.search_weight, x.annual_sales
     Sort Method: top-N heapsort  Memory: 30kB
     ->  Subquery Scan on x  (cost=665492.58..676491.33 rows=1466 width=939) (actual time=18344.715..18546.830 rows=151527 loops=1)
           Filter: (x.r = 1)
           Rows Removed by Filter: 20672
           ->  WindowAgg  (cost=665492.58..672825.08 rows=293300 width=931) (actual time=18344.710..18511.625 rows=172199 loops=1)
                 ->  Sort  (cost=665492.58..666225.83 rows=293300 width=931) (actual time=18344.702..18359.145 rows=172199 loops=1)
                       Sort Key: companies.world_hq_sid, (CASE WHEN ((companies.address_state)::text = 'CA'::text) THEN 1 ELSE 0 END), companies.sort_order
                       Sort Method: quicksort  Memory: 108613kB
                       ->  Bitmap Heap Scan on companies  (cost=17236.64..518555.98 rows=293300 width=931) (actual time=1861.665..17999.806 rows=172199 loops=1)
                             Recheck Cond: ((upper((name)::text) ~~ 'CO%'::text) OR (upper((marketing_alias)::text) ~~ 'CO%'::text))
                             Filter: ((upper((name)::text) ~~ 'CO%'::text) OR (upper((marketing_alias)::text) ~~ 'CO%'::text))
                             ->  BitmapOr  (cost=17236.64..17236.64 rows=196219 width=0) (actual time=1829.061..1829.061 rows=0 loops=1)
                                   ->  Bitmap Index Scan on companies_name_pattern_upper_idx  (cost=0.00..8987.98 rows=97772 width=0) (actual time=971.331..971.331 rows=169390 loops=1)
                                         Index Cond: ((upper((name)::text) ~>=~ 'CO'::text) AND (upper((name)::text) ~<~ 'CP'::text))
                                   ->  Bitmap Index Scan on companies_alias_pattern_upper_idx  (cost=0.00..8102.02 rows=98447 width=0) (actual time=857.728..857.728 rows=170616 loops=1)
                                         Index Cond: ((upper((marketing_alias)::text) ~>=~ 'CO'::text) AND (upper((marketing_alias)::text) ~<~ 'CP'::text))

我已经将 work_mem 和 shared_buffers 增加到 100M。

如您所见，此查询在 18 秒内返回。奇怪的是，对于不同的起始字符，从 400 毫秒（可接受）到 30 秒（非常不可接受）的结果都是全面的。Postgres 大师，我的问题是，我是否期望太多的 postgresql 能够始终如一地快速执行这样的查询？有没有办法可以加快速度？

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2 回答 2

1 
select *
from (
    select distinct on (world_hq_sid)
        world_hq_sid,
        (address_country_code = 'US')::int + (address_state = 'CA')::int address_weight,
        sort_order,
        search_weight, annual_sales,
        sid, name, marketing_alias,
        address_country_code, address_state
    from companies
    where
        upper(name) LIKE upper('co%')
        OR upper(marketing_alias) LIKE upper('co%')
    order by 1, 2 desc, 3
) s
order by
    address_weight desc,
    search_weight,
    annual_sales desc
limit 10
于 2013-05-21T23:45:19.853 回答
0

对于自动完成，可以使用三元组搜索。

pg_trgm 模块。

CREATE EXTENSION pg_trgm;
ALTER TABLE companies ADD COLUMN name_trgm TEXT NULL;
UPDATE companies SET name_trgm = UPPER(name);

CREATE INDEX companies_name_trgm_gin_idx ON companies USING GIN (name_trgm gin_trgm_ops);
于 2013-05-21T23:34:04.743 回答