Performance Tuning Factors


Performance Tuning Factors

Hi Every One,

On Factors Do we decide it is a bad query in teradata


Impact CPU,
IO CPU Ratio,
CPU IO Ratio,
CPU Efficiency,
Query Time

Please help me out.

Thanks in advance.

Bharath Katukota

Re: Performance Tuning Factors

There could be multiple factors. Below are some i can think of

Queries which does lot of redistribution and results in product joins
Queries consuming high cpu, IO, spool space usage (again this is relative as big table joins take high cpu compared to small table joins)

Hope this answers your question.

Re: Performance Tuning Factors

what is ImpactCPU? what does it indicate?

Re: Performance Tuning Factors

It's been a while, but if I remember correctly, impact CPU is a way of measuring the impact that a particular highly skewed query has on the system. It takes a look at the highest CPU across each AMP and multiplies it by the number of AMPs. This gives you a picture of the impact to system resources the query has.

Re: Performance Tuning Factors

Impact CPU = MaxAmpCPUTime * (HashAMP() + 1)