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From Venkat <rkre...@gmail.com>
Subject Re: timestamp order
Date Wed, 24 Apr 2013 00:12:43 GMT
Thanks Keith, This is a great suggestion. Trying out the reverse of
that .. (999999999999
- timestamp)+machineID

Thanks !


On Tue, Apr 23, 2013 at 7:59 AM, Keith Turner <keith@deenlo.com> wrote:

>
>
>
> On Mon, Apr 22, 2013 at 8:59 PM, Venkat <rkreddy@gmail.com> wrote:
>
>> It looks like versioningiterator gives me the past versions for a cell
>>  .... but I need to look across rows ..
>>
>> I am inserting time series data for set of machines into accumulo and i
>> am using a combo of machineid + timestamp as the row ID and metric as the
>> cq.  So for me to get the last time a metric has been inserted for an
>> asset, i need to look across row IDs and get the last 5 rows that got
>> inserted with that metric ...
>>
>
> You could consider sorting your data such that the most recent timestamps
> come first.   If you insert (machineid + (999999999999 - timestamp)).   To
> get the 5 most recent row, start scanning at (machineid + 999999999999) and
> stop when you have 5 rows.   I picked a completely arbitrary number of 9's
> for the example, not sure what time resolution its appropriate for.
>
>
>>
>>
>>
>> On Mon, Apr 22, 2013 at 2:48 PM, Billie Rinaldi <billie.rinaldi@gmail.com
>> > wrote:
>>
>>> You could use a VersioningIterator with maxVersions set to 5.
>>>
>>> Billie
>>>
>>>
>>>
>>> On Mon, Apr 22, 2013 at 11:29 AM, Venkat <rkreddy@gmail.com> wrote:
>>>
>>>> hello accumulo,
>>>>
>>>> what is a good way to get rows in chronological order ?   i am trying
>>>> to get to a use case of "give me the last 5 inserted for this particular
>>>> cf, cq ..."  timestampfilter works well when I know the times but i dont
>>>> know the exact times of insertion.
>>>>
>>>
>>>
>>
>

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