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From "Hiller, Dean" <Dean.Hil...@nrel.gov>
Subject Re: ColumnFamilyInputFormat - error when column name is UUID
Date Tue, 30 Oct 2012 12:30:51 GMT
If you want to avoid the type 1 opaque type uuid's, PlayOrm also does a simple key generator
if you do

@NoSqlId
Private String id;

It uses the simple hostname(not mac) like a1, a2, a3 which is the names in our cluster plus
a unique timestamp within the node.  We do not expose the subdomain that is used so in general
we though it not to be as much of a security risk.  In this fashion, we sometimes have web
pages with the hidden id field that has those strings in it.

Both of these are guaranteed to be unique.  Other types are guaranteed to be unique 9.99999%
of the time(some really high threshold)

Dean

From: Marcelo Elias Del Valle <mvallebr@gmail.com<mailto:mvallebr@gmail.com>>
Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
Date: Monday, October 29, 2012 3:31 PM
To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
Subject: Re: ColumnFamilyInputFormat - error when column name is UUID

Dean,

     Are type 1 UUIDs the best ones to use if I want to avoid conflict? I saw this page: http://en.wikipedia.org/wiki/Universally_unique_identifier
     The only problem with type 1 UUIDs is they are "not opaque"? I know there is one kind
of UUID that can generate two equal values if you generate them at the same milisecond, but
I guess I was confusing them...

Best regards,
Marcelo Valle.

2012/10/29 Hiller, Dean <Dean.Hiller@nrel.gov<mailto:Dean.Hiller@nrel.gov>>
Hmm, this brings the question of what uuid libraries are others using?  I know this one generates
type 1 UUIDs with two longs so it is 16 bytes.

http://johannburkard.de/software/uuid/

Thanks,
Dean

From: Marcelo Elias Del Valle <mvallebr@gmail.com<mailto:mvallebr@gmail.com><mailto:mvallebr@gmail.com<mailto:mvallebr@gmail.com>>>
Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>"
<user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>>
Date: Monday, October 29, 2012 1:17 PM
To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>"
<user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>>
Subject: Re: ColumnFamilyInputFormat - error when column name is UUID

Answering myself: it seems we can't have any non type 1 UUIDs in column names. I used the
UTF8 comparator and saved my UUIDs as strings, it worked.



--
Marcelo Elias Del Valle
http://mvalle.com - @mvallebr

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