Re: Creating Logicals before or after populating a file ?

[Chuck Lewis <CLEWIS@xxxxxxxxxx>]

Evan,

I agree with Larry and Leo !!

At a former job, we had an EOM process that did a BUNCH of Adds, Deletes and
Updates to a HUGE file. This was back when we were on an F70 (remember those 
<BG>
?) and this ONE program would run for HOURS. It had WAY to may logicals over it.
We decided to delete the logicals and let the program run. It reduced the run
time by something like 90 % !!!! Of course you had to recreate the LF's but this
was STILL faster...

A side note - WAY back in my early start in IBM midrange world, when we were
moving from a S/34 to a NEW S/38, we had contractor group in writing an Order
Entry System. The project leader was a programming GENIUS and a GREAT person as
far as taking the time, after hours, on HIS dime to answer any questions me, the
novice and :"budding" programmer had. He had a rule concerning logicals that he
tried to RELIGIOUSLY follow - no more than 3 logicals over a physical, 
especially
LARGE ones,  for all the normal reasons. I KNOW this will start debate, but he
said that you should be able to do everything else in a well written program. 
Key
the PF right and 3 or less LF's. I have tried to stick to this through the years
and for the most part have managed to. It's AMAZING that it really isn't that
hard... IMHO

Chuck

Evan Harris wrote:

> We are about to embark on an exercise that will populate a *large*
> database file (40 million records plus). This file has about 20 logical
> files built over it.
>
> My question is, which is more efficient:
>
> 1. Populating the file and building the logicals ?
>
> 2. Building the logicals and populating the file ?
>
> Any thoughts would be greatly appreciated.
>
> Cheers,
> Evan Harris
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