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Accumulo, mail # user - Accumulo lexicographical order


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RE: Accumulo lexicographical order
Cornish, Duane C. 2014-01-08, 17:38
Great!  Thanks for all the help!

From: Keith Turner [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, January 08, 2014 12:04 PM
To: [EMAIL PROTECTED]
Subject: Re: Accumulo lexicographical order

On Wed, Jan 8, 2014 at 11:50 AM, Mike Drob <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> wrote:

Duane,

Most API methods for inserting values take byte arrays or byte sequences directly. The lexographic order is based on the natural ordering of the bytes, i.e. \x00 sorts before \x01. The methods that take strings will assume UTF-8 encoding and convert for you. If you find a situation where this is not the case, please let us know!

The one exception to all of this is the timestamp part of the key, which is stored in numeric order. I want to say that they are kept in reverse order, but don't remember the exact details off hand.
Thats correct.  The most recent timestamps are sorted first.  Sorted as signed long.

I'm on my phone, so finding the exact place where this is documented will be a challenge, but I would expect it to be part of our user manual on accumulo.apache.org<http://accumulo.apache.org>

Mike
On Jan 8, 2014 8:26 AM, "Cornish, Duane C." <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> wrote:
Accumulo Users,

I know Accumulo keys are sorted in lexicographical order in the tables.  Where can I find the specification defining that order?  For example, what lexicographical order are symbols in?  Is the order the same as the numerical order of UTF-8 encoding, ASCII encoding, or some other encoding scheme?

Thanks in advance,
Duane Cornish