Unnecessary IO and Product Join Indicators

Database

Unnecessary IO and Product Join Indicators

what are Unnecessary-IO and Product Join Indicators in Teradata. How are these metrics determined for a query?

1 REPLY
Senior Apprentice

Re: Unnecessary IO and Product Join Indicators

Hi,

 

They are commonly used metrics that may indicate a porrly performing query.

 

Product join Indicator (PJI) = cpu ms per IO = 1000.00 * ampcputime / totaliocount (using columns in dbqlogtbl).

- a high value may indicate a large product join

 

Unnecessary IO indicator (UII) = IO per cpu sec = totaliocount / (ampcputime * 1000.00)

- a high value may indicate scanning a large table

 

Also see: https://community.teradata.com/t5/Analytics/UII-and-PJI/td-p/22138

(or of course just google 'teradata pji calculation' or 'teradata uii calculation')

 

Cheers,

Dave

Ward Analytics Ltd - information in motion
www: http://www.ward-analytics.com