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Accumulo >> mail # user >> timestamp order


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Re: timestamp order
That approach will tend to hot-spot on ingest: the latest updates will
always go to the first tablet.  Maybe that's ok, but you might want some
scheme to spread those updates to other tablets.

-Eric

On Tue, Apr 23, 2013 at 8:12 PM, Venkat <[EMAIL PROTECTED]> wrote:

> 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 <[EMAIL PROTECTED]> wrote:
>
>>
>>
>>
>> On Mon, Apr 22, 2013 at 8:59 PM, Venkat <[EMAIL PROTECTED]> 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 <
>>> [EMAIL PROTECTED]> wrote:
>>>
>>>> You could use a VersioningIterator with maxVersions set to 5.
>>>>
>>>> Billie
>>>>
>>>>
>>>>
>>>> On Mon, Apr 22, 2013 at 11:29 AM, Venkat <[EMAIL PROTECTED]> 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.
>>>>>
>>>>
>>>>
>>>
>>
>