Re: Expert Cache

I do not see a contradiction here.
"Locality of reference" is applicable not only to database objects.

    Alexei Pytel
always speaking for myself only

"We have all reasons to assume that our assumptions are not unreasonable."



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Re: Expert Cache






Hi Alexei

This is interesting - how does this relate to QWCCHGTN API? Everything 
there seems related to database objects - *CALC is equivalent to tuning 
type 3, correct? And *FIXED to type 0 - with user control in between? And 
in that documentation it is speaking of the "locality of reference".

But is this expert cache, then, or something different?

Thanks
Vern

-------------- Original message -------------- 
From: Alexei Pytel <pytel@xxxxxxxxxx> 

Of course, this has the best effect when file access is basically 
consistent, because it affects all IO requests, not table by table. 

Expert cache works object by object. It tries to recognize the pattern 

of 

access to each object 
and optimize paging activity for that object. 

Leaving it *FIXED uses a 4KB request size no matter what is going on. 

Each object has a default transfer size, which is not necessarily 4KB. 
This is what it falls back to when Expert cache is off. 
For example, QUSCRTUS API (Create user space) allows to set the transfer 

size. 
Look for optional parameter group 3. 

http://publib.boulder.ibm.com/infocenter/iseries/v5r4/topic/apis/quscrtus.htm 

Alexei Pytel 
always speaking for myself 


"We have all reasons to assume that our assumptions are not 

unreasonable." 

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