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

[John Myers - MM <jmyersmm@xxxxxxxxxx>]

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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