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HBase >> mail # user >> Using doubles and longs as ordering row values


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Jonathan Bishop 2012-11-05, 18:41
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Re: Using doubles and longs as ordering row values
On Mon, Nov 5, 2012 at 10:41 AM, Jonathan Bishop <[EMAIL PROTECTED]> wrote:
> Hi,
>
> In my application my row values are doubles. I would like my scans to
> traverse the rows in order of increasing values.
>
> But if I simply use
>
> double d  = ....
> byte[] row = Bytes.toBytes(d);
>
> I will get an ordering which is based on the byte values of doubles, not on
> the value of the doubles themselves.

It's the same ordering as long as you don't use negative values.

>
> I see also that integer values have the same issue due to the first bit
> being the sign bit. So negative values will come after positive values.
>
> Any suggestions?

Don't use row keys that can be negative? :)

Also don't use a single number as a row key, see
http://hbase.apache.org/book.html#rowkey.design

J-D
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anil gupta 2012-11-05, 22:57
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lars hofhansl 2012-11-06, 00:01
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Dave Latham 2012-11-06, 00:26
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Dave Latham 2012-11-06, 00:27
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Jonathan Bishop 2012-11-06, 05:07
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David Koch 2012-12-01, 15:01
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Marcos Ortiz 2012-12-01, 15:27