

Extracting timestamp and MAC address from UUIDs - mooreds
http://rpbouman.blogspot.com/2014/06/mysql-extracting-timstamp-and-mac.html

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geofft
There's a story that the creator of 1999's "Melissa" virus was found via a
GUID in the Word document that included their MAC address.

(I'm having trouble confirming the veracity of this, since the web is full of
citogenesis that links to [http://www.zdnet.com/news/tracking-melissas-alter-
egos/10197...](http://www.zdnet.com/news/tracking-melissas-alter-egos/101974)
which isn't super clear, but it's a good story nonetheless.)

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elmin
An alternative that was posted here a week or so ago:
[https://eager.io/blog/how-long-does-an-id-need-to-
be/](https://eager.io/blog/how-long-does-an-id-need-to-be/)

~~~
klodolph
Or you could just use type 4 UUIDs. We know 64 bits is likely too small, and
128 bits is likely enough. Why bother saving a few bits here and there, if you
already have a working solution?

~~~
girvo
For unique IDs in databases, you want them to have common prefixes such that
they are kept in rough time order in the database's backend, otherwise your
indexes can end up huge and degrade performance (especially in MySQL, that's
where we got bitten by it). That's where Type 1s are great, but of course this
article shows a major downside.

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pbbakkum
We encountered some of these same issues and wrote this library to mitigate
them: [https://github.com/groupon/locality-
uuid.java](https://github.com/groupon/locality-uuid.java). I think UUIDs make
good unique ids overall, particularly in distributed environments where id
generation can't be coordinated, but should be used carefully, as the article
notes.

~~~
X-Istence
Why not just use UUID 4:

[http://en.wikipedia.org/wiki/Universally_unique_identifier#V...](http://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_.28random.29)

This will have an better distribution for when they are used as keys as well.

~~~
e12e
As far as I can tell, neither MySQL, nor MariaDB has a function for generating
type 4 UUIDs. It's of course possible to generate the UUIDs on the client
side, but then it's not really an alternative to auto-incrementing surrogate
keys.

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eridal
Why tapping on any text will navigate to another page? I've seen the same
before, on blogs using the same theme. Is that to increase hits? It's really
annoying for the reader experience!

~~~
pmontra
That theme has a slide-to-next/prev-post feature. Tapping shouldn't activate
it but maybe it's buggy with some browsers. Opera Android doesn't (same engine
of Chrome).

