RE: logical file access paths

I may not have understood the original question.  (I've done that before.)

If your question is "Does changing a key value in a single record require a
complete rebuild of the access path?", the answer is no.  Updating, adding,
or deleting one record means that the operating system does a small piece of
housekeeping on the access path probably involving establishing the
relationship between the new/changed/deleted record and its predecessor and
successor.  When you build an access path from scratch, you have to do this
for every record in the file.

> -----Original Message-----
> From: Colin Thorpe [mailto:Colin@IBS-PUBLIC-SERVICES.CO.UK]
> Sent: Thursday, April 13, 2000 1:14 AM
> To: 'RPG400-L@midrange.com'
> Subject: logical file access paths
> 
> 
> Thanks to all who responded to the original post....
> 
> >The initial build has to read the entire file, build the key 
> table, (Access
> >Path), then sort the Access Path and write it to a file.  
> This initial read
> >of the entire 10mil record file takes a while.  
> Adding/Deleting/Updating
> >record keys is done rather quickly on a record by record 
> basis.  Don't you
> >just love the power of the AS400s native data base.
> 
> 
> A couple of points for clarity........
> 
> 1. This is not a real issue, it is something we are 
> discussing in our office
> at the moment.
> 
> 2. I understand the above but,
>     If you change/update a record that is part of the key (ie 
> order/access
> path etc) why does it not have to 
>     rebuild the order/access path to accomodate this new 
> record order and
> therefore take some time.
> 
> Thanks 
> 
> 
> Colin 
>        
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