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From Carlo Pires <carlopi...@gmail.com>
Subject Re: Highest and lowest valid values for UUIDs/TimeUUIDs
Date Wed, 25 Apr 2012 12:11:11 GMT
Tyler,

A think you could add this values as python constants to pycassa. This
would be very useful for many people.

2012/4/24 Drew Kutcharian <drew@venarc.com>

> Nice, that's exactly what I was looking for.
>
>
> On Apr 24, 2012, at 11:21 AM, Tyler Hobbs wrote:
>
> Oh, I just realized that you're asking about the lowest TimeUUID
> *overall*, not just for a particular timestamp. Sorry.
>
> The lowest possible TimeUUID is '00000000-0000-1000-8080-808080808080'.
> The highest is 'ffffffff-ffff-1fff-bf7f-7f7f7f7f7f7f'.
>
> On Tue, Apr 24, 2012 at 12:47 PM, Drew Kutcharian <drew@venarc.com> wrote:
>
>> Thanks. So looking at the code, to get the lowest possible TimeUUID value
>> using your function I should just call convert_time_to_uuid(0) ?
>>
>>
>> On Apr 24, 2012, at 10:15 AM, Tyler Hobbs wrote:
>>
>> Yes, I have tested it.
>>
>> On Tue, Apr 24, 2012 at 12:08 PM, Drew Kutcharian <drew@venarc.com>wrote:
>>
>>> Thanks Tyler. So have you actually tried this with Cassandra?
>>>
>>>
>>>
>>> On Apr 24, 2012, at 5:44 AM, Tyler Hobbs wrote:
>>>
>>> At least for TimeUUIDs, this email I sent to client-dev@ a couple of
>>> weeks ago should help to explain things:
>>> http://www.mail-archive.com/client-dev@cassandra.apache.org/msg00125.html
>>>
>>> Looking at the linked pycassa code might be the most useful thing.
>>>
>>> On Tue, Apr 24, 2012 at 1:46 AM, Drew Kutcharian <drew@venarc.com>wrote:
>>>
>>>> Hi All,
>>>>
>>>> Considering that UUIDs are compared as numbers in Java [1], what are
>>>> the lowest and highest possible values a valid UUID can have? How about
>>>> TimeUUIDs?
>>>>
>>>> The reason I ask is that I would like to pick a "default" UUID value in
>>>> a composite column definition like Composite(UUID1, UUID2) where UUID1 can
>>>> be set to the default value if not supplied. In addition, it'd be nice if
>>>> the "default" columns are always sorted before the rest of the columns.
>>>>
>>>> I was thinking of just doing "new UUID(Long.MAX_VALUE, Long.MAX_VALUE)"
>>>> or "new UUID(Long.MIN_VALUE, Long.MIN_VALUE)" but not sure if that's going
>>>> to cause other issues that I'm not aware of.
>>>>
>>>> Thanks,
>>>>
>>>> Drew
>>>>
>>>>
>>>> [1] Here's the compareTo of java.util.UUID as a reference:
>>>>
>>>> public int compareTo(UUID val) {
>>>>    // The ordering is intentionally set up so that the UUIDs
>>>>    // can simply be numerically compared as two numbers
>>>>    return (this.mostSigBits < val.mostSigBits ? -1 :
>>>>            (this.mostSigBits > val.mostSigBits ? 1 :
>>>>             (this.leastSigBits < val.leastSigBits ? -1 :
>>>>              (this.leastSigBits > val.leastSigBits ? 1 :
>>>>               0))));
>>>> }
>>>>
>>>>
>>>
>>>
>>> --
>>> Tyler Hobbs
>>> DataStax <http://datastax.com/>
>>>
>>>
>>>
>>
>>
>> --
>> Tyler Hobbs
>> DataStax <http://datastax.com/>
>>
>>
>>
>
>
> --
> Tyler Hobbs
> DataStax <http://datastax.com/>
>
>
>


-- 
  Carlo Pires
  62 8209-1444 TIM
  62 3251-1383
  Skype: carlopires

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