Re: Cobol I/O Modules and Blocking

[Terry Grider <tgrider@xxxxxxxxxxxx>]

Hi Eric,

  Thanks for the reply.  Sorry to be so long in answering, but
I finally got some vacation time!  No triggers on any of these
files. It appears IBM is trying to do the thinking for us and
deciding that since file access methods are defined in the
program where blocking of records would not be suitable,
they will just disable any blocking regardless of how the
file is actually opened!  File access methods are stored in
the object description of the program and apparently,
they are all considered when the Data Path is opened.
It doesn't matter if you put SEQONLY(*YES) in an
OVRDBF CL for the file.  I am basing my conclusion
that blocking is not working on the Work with Job, option
14, PF11 display which shows the file i/o count and the
relative record value maintaining a 1 to 1 relationship. In
programs we have written in-house which do not use these
general purpose i/o routines, and simply define the files within
the program itself, these values show a 1 to 10 or whatever
the blocking factor chosen happens to be and it processes
the file much quicker.  This is more important to us than it
might be to some, because these are very large files, some
and large as 10 GB and blocking makes a huge difference in
the time it takes to read though it sequentially.

Thanks again,
Terry Grider

ericadelong@pmsc.com wrote:

>      I ran across a possible cause for this last night. Are you by any
>      chance using a trigger program on the file you are trying to process
>      sequentially? As I understand it, the trigger program _may_ be forcing
>      all I/O to be processed a record at a time. This is to allow the
>      trigger to fire on each record that is processed. Could this be the
>      answer to your problem?
>
>      Eric A DeLong
>      ericadelong@pmsc.com
>
> ______________________________ Reply Separator 
>_________________________________
> Subject: Cobol I/O Modules and Blocking
> Author:  <MIDRANGE-L@midrange.com > at INTERNET
> Date:    7/7/98 9:39 AM
>
> Hi all,
>   We have a system where the vendor has coded all file i/o into
> dynamically called modules.  These modules have all possible

> file access methods available (sequential, random, input, output, i/o).

>  The problem comes when these module are used to process

> a file sequentially and it would be a great benefit to block the file,
> but because the system sees the other processing methods defined

> in the module, it disables any blocking paramaters we try to use.

>  Short of rewriting these modules, (there are hundreds of them)
> does anyone know a way to enable blocking using these modules?
>
> TIA
> Terry Grider
>



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