" On a large dataset, one can use this to great advantage, as you can
start reading serially from HWM minus 500,000 instead of reading the
entire millions."

Or you could simply read serially backwards?


-----Original Message-----
From: HP-3000 Systems Discussion [mailto:HP3000-L@RAVEN.UTC.EDU] On
Behalf Of Wyell Grunwald
Sent: Tuesday, April 22, 2008 11:06 AM
To: HP3000-L@RAVEN.UTC.EDU
Subject: Re: [HP3000-L] Behavior of Image with HWPUT set

The default behavior of TurboImage is to use the delete chain for new
entries first, then add entries at the highwater mark. By using DBUTIL
to enable HWMPUT (HighWater Mark Put), new entries are added at the
highwater mark until the capacity is reached, then the delete chain is
used. Personally, I like the HWMPUT enabled on all my databases, as it
keeps the entries chronological on a serial read (as long as the
capacity is not reached). On a large dataset, one can use this to great
advantage, as you can start reading serially from HWM minus 500,000
instead of reading the entire millions.

-------------- Original message --------------
From: John Bawden

> We had a dataset with HWPUT enabled and found that it reported the

high water
> mark equal to the capacity of the set yet there were no problems with

records
> being added to the set. So it got us to thinking that when HWM was

equal to
> capacity, then Image, to save us from ourselves, reverted to using the

delete
> chain to add new records. Does anyone know if this is what happens?
>
>
> John Bawden
> Homestead3000 Consulting
> MPE Forever
>
> * To join/leave the list, search archives, change list settings, *
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