SQL查询性能问题-如何使用哈希技术? [英] SQL Query performance issue - How to use hashing technique?

问题描述

我遇到了一个简单的查询问题，这需要花费大量时间.我有一个带有Dummy_Table的表，其中的列A，B，C等多达15列.

我有一个简单的查询，就像这样.

I am facing a problem with a simple query which is taking lot of time. I have a table with Dummy_Table with coumns A, B, C etc upto 15 columns.

I have a simple query which goes like this.

select count(*) from Dummy_Table where A = ''bdfb'' and B = ''gg'' and Z = ''ggdg'' and P = ''nmlk'' and S = ''giuh''

该Dummy_Table已获得约3000万条记录.
上面的查询大约需要30秒才能执行.我的目标是将其降低到不到1秒.

我尝试设置适当的索引，将Index和where子句的顺序保持不变，但无法获得所需的结果.

我会要求该论坛中的任何人为我提供适当的解决方案.我还听说我们可以通过使用哈希函数来提高性能.任何人都可以帮助我有关如何做到这一点.

预先感谢.

This Dummy_Table has got about 30 million records.
The above query is taking about 30 secs to execute. My target is to bring it down to less than 1 sec.

I tried setting the proper indexes, keeping the order of Index and where clause as same but I am unable to get the required result.

I would request anyone in this forum to suggest me an appropriate solution. I also heard that we can improve the performance by using Hashing functions. Can anyone help me regarding how we can do that.

Thanks in advance.

推荐答案

您可以尝试使用临时表-但实际上，将IMO的30秒降为1太陡了.

You can try using temp tables - but really, bringing 30 secs down to 1 is too steep a requirement IMO.

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