RE: Single level store & record blocking on update files (was RE:Where is IBM?)

[Dan <dbcemid@xxxxxxxxx>]

Since we do not have Performance Tools (and even if we did, I don't know how to 
use them), I am
unable to chart that path.  

However, in my seat of the pants observation, on a fairly static system, with 
enough data that
should bear out any performance differences, there was none, nada, blotto, 
zilch.

I even tried SETOBJACC on the file, and there was no discernable difference 
using that, either.

- Dan

--- John Myers - MM <jmyersmm@xxxxxxxxxx> wrote:
> Dan,
> 
> I think that JT is correct when he said ...
> 
> >My recollection is that I/O count refers to DB operations, and you'd hafta
> >get down to looking at Performance Tool measures on synchronous and
> >asynchonous I/O to get at physical I/O.  (Syncronous being the only one that
> >counts for the bottlenecks.)  There should be a fair correspondence between
> >the DB I/O and physical I/O.
> 
> I'm pretty sure that the IO Count there reflects requests and not actual, 
> physical DB operations.
> 
> I don't have the time today to look these things up ... sorry ... I guess 
> that means that I must give up my claim for lunch!
> 
> John
> 
> At 11:48 AM 4/24/2003, you wrote:
> >--- John Myers - MM <jmyersmm@xxxxxxxxxx> wrote:
> > > Also, don't confuse RPG record blocking with OS/400 record blocking!
> > >
> > > The AS/400 CAN do "blocking" on updates ... it just does it behind the
> > > scenes at the OS/400 level.
> > >
> > > See CRTPF, CRTLF, CHGPF, or OVRDBF parameter FRCRATIO  whose help text 
> > reads:
> ><SNIP>
> >
> >John, I added FRCRATIO(40) to the override as presented in my reply to 
> >Doug, with the same
> >results.  My basis for determining that there is no blocking going on is 
> >that, from WRKJOB's
> >Display Open Files screen, the I/O Count is always double (or one off) 
> >that of the Relative Record
> >number displayed.  It is my understanding that this is a true reflection 
> >of what OS/400 is doing
> >"behind the scenes".  Agreed?
> >
> >Reading the help for FRCRATIO, it is *very* interesting that it refers to 
> >maximum number of
> >records to be *updated* before they are forced into aux stg.  The 
> >implication seems to state that
> >update file record blocking can occur, but I have yet to prove it in 
> >practice.
> >
> >Comments welcomed.
> >
> >- Dan

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