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HBase, mail # user - Re: row filter - binary comparator at certain range


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Tony Duan 2013-10-21, 04:31
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Michael Segel 2013-10-21, 11:36
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Re: row filter - binary comparator at certain range
Michael Segel 2013-10-21, 11:38
Sorry if this double posts... may have used the wrong email first.

On Oct 21, 2013, at 6:36 AM, Michael Segel <[EMAIL PROTECTED]> wrote:

>
> Lets look at what you are trying to do...
>
> You want to take data where the key is a timestamp (long datatype)
> You append it to a salt value 1=10 or 0-9 your example doesn't say...
>
> You have a couple of problems with your choice of a key...
>
> First after your initial 10 splits, you will still end up with writing everything to the left side of the region.
> This means that when the region splits... all writes will still be to the left leaving your regions still 1/2 the size that they could be with the with the exception of your last set of salted regions. In this case 10 which will grow and then split.
>
> Is this a bad thing? Maybe yes, maybe no.
>
> The issue is that you will then have to write 10 queries with a start key and a stop key to get the range of your timestamp.
>
>
> That would work, however...
>
> 1) Justify why you want/need to use a timestamp as a key for the row.
>
> I'd say tell us more about the use case and why the access pattern.
>
> Salting is bad in that the salt is disassociated to the underlying key.
> Taking the key's hash, truncating it and preprending (if this is an actual word) to the key gives you a random key where if you know the rowkey, you can hash it.
>
> My suggestion is that you rethink your key...
>
>
>
> On Oct 20, 2013, at 11:31 PM, Tony Duan <[EMAIL PROTECTED]> wrote:
>
>> Alex Vasilenko <aa.vasilenko@...> writes:
>>
>>>
>>> Lars,
>>>
>>> But how it will behave, when I have salt at the beginning of the key to
>>> properly shard table across regions? Imagine row key of format
>>> salt:timestamp and rows goes like this:
>>> ...
>>> 1:15
>>> 1:16
>>> 1:17
>>> 1:23
>>> 2:3
>>> 2:5
>>> 2:12
>>> 2:15
>>> 2:19
>>> 2:25
>>> ...
>>>
>>> And I want to find all rows, that has second part (timestamp) in range
>>> 15-25. What startKey and endKey should be used?
>>>
>>> Alexandr Vasilenko
>>> Web Developer
>>> Skype:menterr
>>> mob: +38097-611-45-99
>>>
>>> 2012/2/9 lars hofhansl <lhofhansl@...>
>> Hi,
>> Alexandr Vasilenko
>> Have you ever resolved this issue?i am also facing this iusse.
>> i also want implement this functionality.
>> Imagine row key of format
>> salt:timestamp and rows goes like this:
>> ...
>> 1:15
>> 1:16
>> 1:17
>> 1:23
>> 2:3
>> 2:5
>> 2:12
>> 2:15
>> 2:19
>> 2:25
>> ...
>>
>> And I want to find all rows, that has second part (timestamp) in range
>> 15-25.
>>
>> Could you please tell me how you resolve this ?
>> thanks  in advance.
>>
>>
>> Tony duan
>>
>>
>
> The opinions expressed here are mine, while they may reflect a cognitive thought, that is purely accidental.
> Use at your own risk.
> Michael Segel
> michael_segel (AT) hotmail.com
>
>
>
>
>
>
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Premal Shah 2013-10-21, 05:42
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James Taylor 2013-10-21, 06:05
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Vladimir Rodionov 2013-10-21, 16:14
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James Taylor 2013-10-21, 16:37
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Michael Segel 2013-10-21, 20:05
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James Taylor 2013-10-21, 20:26
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Michael Segel 2013-10-21, 20:48
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James Taylor 2013-10-21, 22:07
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Michael Segel 2013-10-22, 00:58
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James Taylor 2013-10-22, 03:54
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Asaf Mesika 2013-11-01, 07:25
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Vladimir Rodionov 2013-10-21, 16:50
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Vladimir Rodionov 2013-10-21, 16:36
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Tony Duan 2013-10-22, 07:55