RE: Gauge32 as an INDEX (was: Index values of zero)

["Presuhn, Randy" <Randy_Presuhn@bmc.com>]

Hi -

> From: C. M. Heard [mailto:heard@pobox.com]
> Sent: Thursday, January 02, 2003 14:54
> To: mreview@ops.ietf.org
> Subject: Gauge32 as an INDEX (was: Index values of zero)
...
> > What is so dangerous about the use of Gauge32 as an
> > index that it should warrant a "NOT RECOMMENDED"?
> 
> The original text treated Gauge32 and Unsigned32 as synonymous, and
> both Juergen and Bert voiced objections on the grounds that 
> the special
> semantics attached to Gauge32 make it an inappropriate SYNTAX for a
> variable that appears in an INDEX clause.  That is, it was 
> perceived as
> something that you SHOULD NOT do.  I had to agree with that, because I
> can't think of a situation where I would want to use Gauge32 
> in an INDEX
> clause other than in a MIB module that was translated from SMIv1.
...

Reasoning like this led to the unfortunate situation
with 64-bit integers.  We shouldn't use our lack of
imagination as the reason for a prohibition.  When
someone *does* come up with a reason to want to do it,
we'll be guilty of yet another CLR.

Contrived Example:

Track the topN most over-heated components in a system.
The obvious indexes for such a dynamically changing table
would be the temperature (Gauge32) and the component's
id.

I'm sure someone else can come up with something less
contrived, or will make the argument that the Gauge32
should be Unsigned32, but my point remains: we should
not be making recommendations against a particular
construct unless we can explain exactly why using a
construct would be a bad idea.

 ------------------------------------------------------
 Randy Presuhn          BMC Software, Inc.  1-3141
 randy_presuhn@bmc.com  2141 North First Street
 Tel: +1 408 546-1006   San José, California 95131  USA
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 My opinions and BMC's are independent variables.
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