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UUIDs - is it possible that they can be reused
chetany
A Score Level 1
over 7 years ago
I am curious about UUIDS.
So, assume that I have few design objects in an application. And consider I delete an object (maybe a rule), now this object is gone.
Let's say the UUID of deleted object was "delUUID".
Now, I create new design objects. Other team members may also create new objects. And they will have different UUIDS.
Is there a possibility that the UUID of deleted object ("delUUID") be reused?
The answer to this will depend on how the UUIDs are assigned to new design objects when we create them, and whether UUIDS are recycled.
It sounds unlikely that UUIDS can be recycled - but could it happen?
In my opinion, UUIDS are 128 bit, so there are exponentially huge number of permutations - and we have a huge pool of UUIDS to allocate from - so its not possible to run out of UUIDS.
But, still could an old UUID get reused? How likely is it?
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PhilB
Certified Lead Developer
over 7 years ago
It depends on how the UUID is generated. Often there's a time element, so it's nearly impossible. What you're asking for is actually a formalised definition of a UUID, and there's a decent one on wikipedia. For your specific question, you'll want to read here:
en.wikipedia.org/.../Universally_unique_identifier
Short answer: 1 in 17 billion.
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chetany
A Score Level 1
over 7 years ago
Thanks @philb , for the link - so its almost impossible.
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PhilB
Certified Lead Developer
over 7 years ago
Yep; "almost" being the operative word!
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marky
over 7 years ago
We have had issues with the same UUID being associated to different objects created on different environments. So this is possible (and annoying).
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PhilB
Certified Lead Developer
over 7 years ago
That's only where the objects have been created separately on each environment though, right? If the environments were, say, DEV and TEST, that should never happen as one should always import from DEV to TEST rather than creating directly in TEST.
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Sally Mason
Appian Employee
over 7 years ago
It is possible, anything is possible, but it is not at all likely or probable. Again, if you were making and deleting millions and millions of objects, then the likeliness increases every so slightly..
Ideally, you should be designing all your Applications and Objects in Dev, then exporting the App to Test - the UUIDs of each object stay the same, then after testing, promoting the same package to Prod, ensuring the objects and their UUIDs are fixed.
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chetany
A Score Level 1
over 7 years ago
Thank you Sally for the information
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