Re: 2 PDE copies in memory

Discussion created by ca.portal.admin on Aug 31, 2007
Last entry. Varying memory in a PDE program name (which is part of the
index) can cause lots of problems. Program not found, duplicate entries,

Cobol programs that are no longer defined as cobol etc.
So please do not vary a program name.
As Bill Allen said, it will definitely cause index corruption.
That being said, if you REALLY had to vary the name - make sure it fits
alphabetically into the index..
Ed McKinney
IDMS Public Discussion Forum


Re: [IDMSVENDOR-L] 2 PDE copies in memory
"Absolutely, that's why I said ""you had inadvertently dynamically
created...""; key being the 'you' and 'dynamic'. And yes, I've made this
particular mistake (on a test system, long long ago).

As to the index issue; changing the name in the PDE doesn't adjust any of
the structures pointing to this PDE. In particular, I would be concerned
with how IDMS is using offset X'54' in the PDE, described as ""ADDR OF NEXT

CONJECTURE: If IDMS expects these to be in ascending sequence, and if the
index structure points into approximate locations in this string which are
then sequentially searched, it seems likely that you could ""break a chain""
this way. Without knowing exactly how the indexing structure is built and
managed I can't predict what will happen if you get this chain out of
sequence, but this is akin to zapping the sort key of a record in a sorted
or index set without adjusing set sequence/SR8 contents. I may work, it may
not; depending on surrounding order/structures.

That said, I agree circumstances might force one to take a chance; worst
case is you end up with a recycle anyway... I just wouldn't want to make
this a common technique.