ca.portal.admin

interesting phenomena (was[IDMSVENDOR-L] Indexes with

Discussion created by ca.portal.admin on Mar 7, 2006
Latest reply on Mar 7, 2006 by ca.portal.admin
Duplicates Problem)

IDMS marks a page as full ONLY when all three things occur:

a store or modify is attempted on a page
the result AFTER the operation is that the page is 70% or more full
and ...
THE OPERATION WAS NOT SUCCESSFUL


so what does that mean? if your record size is such that you can NEVER
get
the area above 70%, the page will NEVER be marked as full and (when
applied to an entire area) IDMS will keep looking forever to put a
to-be-stored record into marked-as-available pages which it can never
do!!

example, if the amount of available space on a page is 10000 bytes, the
consider the following:

a record of (total) size range of 334 - 349 bytes will only store 2 per
page, but will never hit 70%, so will never be marked as full - same for
records in the range of 501 - 699 bytes ( in this case, it could only be
stored once per page but never hit 70%).

I know that no one would design a database under these condition. but
restructures, xpages, or unload/reloads could change the original
definitions .. So, in the simplest case:

if x is the total length to be stored / the available space of an empty
page,

then avoid all record sizes where .333 < x < .500 and .500 < x <
.700
(ideally, below .333 in any case, but at exactly 50% or at/above 70%
will
not cause the phenomena I have described)


confused?
Chris Hoelscher
IDMS & DB2 Database Administrator
Humana Inc
502-710-3038
choelscher@humana.com




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Normal
Re: [IDMSVENDOR-L] interesting phenomena (was[IDMSVENDOR-L] Indexes with Duplicates Problem)
"since you appear to be using a symbolic, can you give us the symbolic
value (s)?


Chris Hoelscher
IDMS & DB2 Database Administrator
Humana Inc
502-710-3038
choelscher@humana.com




The information transmitted is intended only for the person or entity to which it is addressed and may contain CONFIDENTIAL material. If you receive this material/information in error, please contact the sender and delete or destroy the material/information.

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Normal

Normal
Re: Indexes with Duplicates Problem
"I have found often that such a problem is caused by failure to allow enough displacement.

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