topic Re: UUIDGEN not unique? in SAS Programming

UUIDGEN not unique?

Quentin — Fri, 24 Oct 2014 17:09:58 GMT

Hi All,

Was inspired by Chris H blog post on GUIDS to play with them.

Today noticed on SAS 9.3 Linux 64 bit it throws:

4          %put %sysfunc(uuidgen());
WARNING: UUID is not guaranteed to be unique.

Of course there are no guarantees in life or pseudo-random numbers. : )

Wondering if this means the chance of a duplicate is much more than the infinitesimal 1 in 2**128 ?

Did see a couple TS notes about the warning, but nothing that actually described what it meant.

Happy Friday,

--Q.

Re: UUIDGEN not unique?

jakarman — Fri, 24 Oct 2014 18:46:17 GMT

The concept is rather generic Universally unique identifier - Wikipedia, the free encyclopedia

The warning on the dependency on the seed is mentioned. The seed (entropy) is sometimes limited an made repeatable.
It often used as a security ticket or other place to get an indentification.

Re: UUIDGEN not unique?

Quentin — Sun, 26 Oct 2014 21:33:30 GMT

Thanks Jaap. My question is really as to the meaning of the WARNING. It is not thrown on other OSsa / SAS versions. So curious if there was something different about the implementation on 9.3 Linux that made SAS developers decide that it should throw a warning?

Re: UUIDGEN not unique?

jakarman — Mon, 27 Oct 2014 05:04:15 GMT

Quentin there are companions for each OS as there are a lot of differences between them.

I do not wonder why there would be a difference as long a could explain that as being the cause.

On all of those OS systems there is also a lot of history with SAS every fix-level release level can be different.

Is the difference to be explained by something of that I wonder but not getting curious.

What is left and we should get curious is when we see behavorial differences the between OS systems in SAS without any reason.

OK I got that as : SAS is promoting (sales) SAS should behave the same ("C" Java based) on all OS systems as promoted to use the same code. By that the promotional point exchanging an OS should be easy exchanging code should be easy. (This is not in your question: release/Os differences)

Altough the "C" code en Java code can be the same the compiler and rum-time libraries of those are not. Some differences can originate from that level.

I agree that there is something weird as this difference is not to be expected.