Re: Money for nothing and ASH for free

Thanks Kyle. I know you advocated Direct SGA access for the same data, but this is different, correct?

I have the issue of having to manage older 8i/9i databases so I adapted 10g's ASH and Metrics ideas in a slightly different way and wrote some code that could be used as the basis of a 'backport' of these tools. Actually presented these ideas as a paper at COLLAB 06 and OOW 06, but stopped there and did not actually develop that into a tool (I just display/spool the simulated ASH output and interpret it as I see it). Let me know if you would like to see that paper. You can probably use that to expand this concept to ADDM....

John

On 6/20/07, kyle Hailey <kylelf_at_gmail.com> wrote:
>
>
> If you are on 10g and already have the performance pack, you can probably
> skip this email.
>
> Some people have been complaining about the licensing of the performance
> packs. I agree it's weird that v$active_session_history is there but you
> aren't suppose to query it. On the other hand I think the performance pack
> is definitely worth it if you are working on an important database where
> slowdowns or outages have financial impact.
>
> On the other hand, if you don't want to pay, can't pay or if you are on
> version 7, 8 or 9 then you can simulate ASH.
> I've put together a plsql package that simulates ASH on
> http://www.perfvision.com/ash.php
> Active Session History is an amazingly rich sort of peformance data and half
> the fun is just thinking of new ways to mine the data.
>
> Things you can do are graph system load over time, find the longest running
> SQL, find the top SQL by cpu or wait, or see the resource breakdown for a
> single SQL etc etc
>
> This paper explains a bit of ASH power
> http://www.perfvision.com/papers/Sampling.pdf
>
> Examples of some SQL and output from querying ASH data are on
> http://www.perfvision.com/sql/ash/note.html
> One cool thing is, even if you are on 10g, the queries from the simulated
> ASH should be roughly compatible with v$active_session_history since it's
> basically the same structure and columns. There are a few differences
> though.
>
> Best Wishes
> Kyle Hailey
> http://perfvision.com
>
>

-- 
John Kanagaraj <><
DB Soft Inc
Phone: 408-970-7002 (W)

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