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From Tyler Hobbs <ty...@datastax.com>
Subject Re: Highest and lowest valid values for UUIDs/TimeUUIDs
Date Wed, 25 Apr 2012 18:09:22 GMT
Good idea.  Done here:
https://github.com/pycassa/pycassa/commit/2390363066c7efd79bdd2f27cd2d4496f692abf4

On Wed, Apr 25, 2012 at 7:11 AM, Carlo Pires <carlopires@gmail.com> wrote:

> 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
>



-- 
Tyler Hobbs
DataStax <http://datastax.com/>

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