Re: Index Advisor question

[Timothy P Clark <timclark@xxxxxxxxxx>]

> Does anyone know what it means when the Index Advisor shows "Source 
> for statistics" as the Reason Advised? This site http://
> pic.dhe.ibm.com/infocenter/iseries/v7r1m0/index.jsp does not show 
> that as a valid value for the column.  We are getting this on 7 of 
> our top 10 "most expensive" advised indexes. When we look at the 
> existing indexes the index the advisor thinks should be created 
> already exists.

Hi Mike,

This comes from new function included with a technology refresh after 7.1 
became generally available, so it is not in the InfoCenter. However, it is 
documented with other post-GA features at 
http://preview.tinyurl.com/kbfh8oy. It looks like the "Source for 
statistics" reason code isn't specifically mentioned there, but that code 
basically means that the most recently recorded use of the corresponding 
maintained temporary index was to provide statistics information to the 
query optimizer. The new index advisor information is intended to give 
additional insight into the benefit that creating an advised index may 
offer.

Hope that helps,
Tim