Impact CPU values from performance perspective

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Teradata Employee

Impact CPU values from performance perspective

Hi

 

I have a question regarding the role of impact CPU in query performance. I know that in most cases impact CPU is higher than request CPU and if the impact CPU is 100 times higher than request then the query is highly skewed and should be tuned (correct me if I am wrong here).

I have script on Teradata which checks the  performance of queries running in our daily batches  and generates a report everyday. The performance of queries is based on query parallel effiency, PJI, UII. Based on different values as agreed with client, we highlight the queries as Red, Amber or Green . The queries which are red are high priority for tuning and amber ones as well.

The script does not check the impact CPU values which results in an SQL which is green with performance parameters (e.g Parallel efficiency>80%, PJI <2, UII<2 and Impact CPU> 20000) whicih should be red if the script consider impact cpu values as well.

Now my question is how to determine the range of impact cpu values for which the SQL should be green (ok) or red (candidate for query tuning) in relation to other performance parameters as mentioned above? And if we have to compare each SQL's request CPU to impact CPU values, how greater the impact CPU values be to highlight the query as red (candidate for tuning).

 

Thanks in advance

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2 REPLIES 2
Teradata Employee

Re: Impact CPU values from performance perspective

@dnoeth  @Fred 

I have seen many posts on performance from you guys.

 

Do you have any valuable suggestions to my question?

 

Thanks in advance

 

Teradata Employee

Re: Impact CPU values from performance perspective

Your question is a little confusing. You say the script does not check impact cpu and yet, impact cpu is listed as one of the critieria ??

 

"The script does not check the impact CPU values which results in an SQL which is green with performance parameters (e.g Parallel efficiency>80%, PJI <2, UII<2 and Impact CPU> 20000) whicih should be red if the script consider impact cpu values as well."

 

There are no official recommended guidelines for a cpu / impact cpu ratio for tuning.

 

Like with PJI, UII you need to determine as a client what is considered unnacceptable.

 

thanks

 

dave