SQL复制删除数百万行的查询以提高性能

Question

这是一次冒险.我从上一个问题中的循环重复查询开始,但每个循环将覆盖所有1700万条记录,这意味着需要几周时间(仅运行*select count * from MyTable*需要我的服务器4:30分钟使用MSSQL 2005).我从这个网站和这篇文章中发现了一些信息.

并且已经到达下面的查询.问题是,对于任何类型的性能,这是在1700万条记录上运行的正确类型的查询吗？如果不是,那是什么？

SQL QUERY:

DELETE tl_acxiomimport.dbo.tblacxiomlistings
WHERE RecordID in 
(SELECT RecordID
    FROM tl_acxiomimport.dbo.tblacxiomlistings
    EXCEPT
    SELECT RecordID
    FROM (
        SELECT RecordID, Rank() over (Partition BY BusinessName, latitude, longitude,           Phone ORDER BY webaddress DESC, caption1 DESC, caption2 DESC ) AS Rank
    FROM tl_acxiomimport.dbo.tblacxiomlistings
    ) al WHERE Rank = 1)

Answer 1

看到QueryPlan会有所帮助.

这可行吗？

SELECT m.*
into #temp
FROM tl_acxiomimport.dbo.tblacxiomlistings m 
inner join (SELECT RecordID, 
                   Rank() over (Partition BY BusinessName, 
                                             latitude,  
                                             longitude,            
                                             Phone  
                                ORDER BY webaddress DESC,  
                                         caption1 DESC,  
                                         caption2 DESC ) AS Rank
              FROM tl_acxiomimport.dbo.tblacxiomlistings
           ) al on (al.RecordID = m.RecordID and al.Rank = 1)

truncate table tl_acxiomimport.dbo.tblacxiomlistings

insert into tl_acxiomimport.dbo.tblacxiomlistings
     select * from #temp