RE: Logical file access paths

[Joel Fritz <JFritz@xxxxxxxxxxxxxxxx>]

I'm curious about the specific implementation, but I assume an access path
is a tree structure designed for easy insertion and deletion of nodes.
Changing the access path by one record shouldn't take too long for the same
reason that one lookup doesn't take very long.

> -----Original Message-----
> From: Colin Thorpe [mailto:Colin@IBS-PUBLIC-SERVICES.CO.UK]
> Sent: Wednesday, April 12, 2000 7:33 AM
> To: 'RPG400-L@midrange.com'
> Subject: Logical file access paths
> 
> 
> 
> Good morning/afternoon,
> 
> I have a question regarding access paths.
> 
> When I create a logical file over a physical file containing 
> 10,000,000
> records, it takes quite some time.
> 
> This is presumably building some kind of Matrix/lookup table?
> 
> This I can understand.
> 
> So then,
> Why, when I update the key to this logical in a Do loop (so 
> attempting to
> re-read the file) , does it not have to update the matrix/lookup table
> (before the re-read) and therefore take a long time to complete.
> 
> ie.
> KEY   SETLL           FILE1
>       DOW             *IN31=*OFF
> KEY   READE   FILE1
>       (CHANGE KEY)
>       UPDATE  FILE1   (move this records position within the logical
> order)
>       ENDDO
> 
> 
> 
> Thanks in advance  
> 
> 
> Colin 
> 
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