At 5:56 PM -0700 3/30/10, Tommy Pham wrote:
On Tue, Mar 30, 2010 at 2:27 PM, Nathan Rixham <nrixham@xxxxxxxxx> wrote:
nope never been able to find any significant advantage; and thus ended
up using http uri's in my own domain space(s) which are always
guaranteed to be unique as I'm issuing them. bonus is that they can be
dereferenced and server as both a universal (resource) identifier and a
locater.
ps: resource = anything that can be named.
Hi Nathan,
I'm interested in hearing your technique of generating your own uuid
if you don't mind sharing :). I'm building a project to test my idea
about search engine and testing of different RDBMSes. So naturally,
it (the app) would crawl the net and I'd have over a 1 billion rows.
Thanks,
Tommy
PS: Here are some info for those who haven't heard of UUID/GUID:
http://affy.blogspot.com/2003/03/why-use-uuid-values.html
http://www.mysqlperformanceblog.com/2007/03/13/to-uuid-or-not-to-uuid/
I've read your links and see the problem presented.
The solution is to create an absolutely unique user ID and therein
lies the problem. How do you create something that is absolutely
unique?
Clearly, if you have one database creating records, an auto_increment
will work for creating an unique number for that's what increment
does. However, if you have more than one database creating records
at the same time, then conflicts would occur.
I had a similar problem recently where I used two fields to identify
a record as being "unique". One field used the exact time the record
was added to the database and the other field was a random number.
Combining the two numbers I believed I had a unique number for the
taks I was doing. Of course, if activity was spread across hundreds
of servers with millions of entries per second, then my method would
not be a solution. As such, the solution should be tailored to the
problem.
Cheers,
tedd
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