Re: Adding an LF decreased performance drastically

[Charles Wilt <charles.wilt@xxxxxxxxx>]

"Is this a normal thing for an LF to eliminate
the blocking factor of the output and make it 1 for 1 or is there something
that we muffed up in the create of the LF?"

Is there a unique key on the LF?  That would do it...

Charles

On Fri, Apr 22, 2022 at 12:18 PM <smith5646midrange@xxxxxxxxx> wrote:

> We have a job that writes about 1.5B records to a PF.  When the job starts,
> it does a CLRPFM and then starts dumping records into the PF.
>
>
>
> We recently added an LF over the PF with no mods to the original program
> (LF
> will be used later in the stream by something else) and the job went from
> approx. 2 hrs to an estimated 11 hrs.  We killed it after the normal 2 hour
> window with less than 20% of the records written.
>
>
>
> While trying to determine why, one thing that we noticed is the job I/O
> count was different with and without the LF.  We found that without the LF,
> the output blocking factor is a pretty decent number of records (I/O count
> is WAY less than RRN).  However, when we created the LF, the I/O count and
> the RRN are almost identical (like blocking is ignored).  The LF is not
> unique keyed, just a normal keyed logical.
>
>
>
> I've never noticed this before but I've never really paid attention to the
> I/O count on output files.  Is this a normal thing for an LF to eliminate
> the blocking factor of the output and make it 1 for 1 or is there something
> that we muffed up in the create of the LF?
>
>
>
> I know we can change the LF to *DLY and stuff like that but we just want to
> understand what happened and why so we know for future reference.
>
>
>
> Thanks.
>
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