postgresql日期提交查询性能

我有两个表。新闻表有7m记录，news_publish表有70m记录当我执行这个查询花费了大量的时间并且很慢。我增加了三个索引进行调整，但查询速度很慢。当我谷歌这个问题，我发现有人建议改变统计到1000，我恰克它，但问题是还没有postgresql日期提交查询性能

alter table khb_news alter submitteddate set statistics 1000; 

SELECT n.id as newsid ,n.title,p.submitteddate as publishdate, 
    n.summary ,n.smallImageid , 
    n.classification ,n.submitteddate as newsdate, 
    p.toorganizationid 

from khb_news n 
    join khb_news_publish p  
     on n.id=p.newsid  
    left join dataitem b on b.id=n.classification 

where 
    n.classification in (1) and n.newstype=60 
    AND n.submitteddate >= '2014/06/01'::timestamp AND n.submitteddate <'2014/08/01'::timestamp and p.toorganizationid=123123 
order by p.id desc 

limit 10 offset 0

指标是：

CREATE INDEX "p.id" 
ON khb_news_publish 
USING btree 
(id DESC); 

CREATE INDEX idx_toorganization 
ON khb_news_publish 
USING btree 
(toorganizationid); 


CREATE INDEX "idx_n.classification_n.newstype_n.submitteddate" 
ON khb_news 
USING btree 
(classification, newstype, submitteddate);

后添加此指标和运行讲解分析我得到这个解释

"Limit (cost=0.99..10100.13 rows=10 width=284) (actual time=24711.831..24712.849 rows=10 loops=1)" 
     " -> Nested Loop (cost=0.99..5946373.12 rows=5888 width=284) (actual time=24711.827..24712.837 rows=10 loops=1)" 
     "  -> Index Scan using "p.id" on khb_news_publish p (cost=0.56..4748906.31 rows=380294 width=32) (actual time=2.068..23338.731 rows=194209 loops=1)" 
     "    Filter: (toorganizationid = 95607)" 
     "    Rows Removed by Filter: 36333074" 
     "  -> Index Scan using khb_news_pkey on khb_news n (cost=0.43..3.14 rows=1 width=260) (actual time=0.006..0.006 rows=0 loops=194209)" 
     "    Index Cond: (id = p.newsid)" 
     "    Filter: ((submitteddate >= '2014-06-01 00:00:00'::timestamp without time zone) AND (submitteddate < '2014-08-01 00:00:00'::timestamp without time zone) AND (newstype = 60) AND (classification = ANY ('{19,20,21}'::bigint[])))" 
     "    Rows Removed by Filter: 1" 
     "Planning time: 3.871 ms" 
     "Execution time: 24712.982 ms"

我加入解释如何更改查询以使其更快？

来源

2016-05-15 ali akbar azizkhani

请修正，使其与解释格式将工作与工具，如https://explain.depesz.com –

我改变它我添加解释在https://explain.depesz.com/s/Gym –

CREATE INDEX“p.id”ON khb_news_publish USING btree（id DESC）;'恕我直言，这应该是一个主键（这将执行一个**唯一**索引）。与其他表类似：首先限制PK + FK，而不是为FK添加支持索引，而不是为其他候选键添加唯一索引，而不是添加一些附加索引来支持典型查询。 – wildplasser

你应该开始与khb_news_publish创建索引（toorganizationid，ID）

CREATE INDEX idx_toorganization_id 
ON khb_news_publish 
USING btree 
(toorganizationid, id);

这应该可以解决这个问题，但你可能还需要指数：

CREATE INDEX idx_id_classification_newstype_submitteddate 
ON khb_news 
USING btree 
(classification, newstype, submitteddate, id);

来源

2016-05-15 10:48:57

我在khb_news中有三个列的索引是drop this index并添加idx_id_classification_newstype_submitteddate？或者添加这个 –

后加这两个索引解释是https://explain.depesz.com/s/SS5H –

我加了这两个索引并在https://explain.depesz.com/s/SS5H中解释 –

postgresql日期提交查询性能

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