Re: Database server jobs and SQL tuning

>  From:    DBale@lear.com (Bale, Dan)
>  
>  Wow.  Is this documented, Al?  Could you point to some kind of reference 
> if you have it handy, please?

I was taught this in IBM school ... one of the programming classes ... I will 
try to dig up where it is in black & white in one of the IBM hand-outs.  The 
IBM Professor took 1/2 an hour or so of drumming this point into us, in 
lecture, exercises, and review questions.  I know it applies in the RPG & CL 
programming that I do ... I just do not know if it applies to SQL, ILE across 
the board.  I have a sneaking suspicion that it may apply to Query.

This was in an IBM programming class in 1999 & it was applicable to RISC 
boxes.

If you want good security - fine, qualify stuff - but understand that there 
is a commensurate performance hit.

> When we use library list, the user profile gets hit ONE time to verify that 
> user has authority to the objects in the list.  If you qualify access to an 
> object by what library it is in, AS/400 has to verify security authority 
> every time you specify the library, irrespective of whether that was 
> validated 2 microseconds ago on another line of code or even is inside the
> library list being used.  
> Thus, depending on how you qualify object locations 
> in your code, and your use of library list, it is possible to totally wipe
> out performance, without gaining any security benefits whatsoever.

Al Macintyre  ©¿©
http://www.cen-elec.com MIS Manager Programmer & Computer Janitor
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