>
>
> My application is a real-time application. It monitors devices in the
> network and displays the top N devices for various parameters averaged over
> a time period. A query may involve anywhere from 10 to 50k devices, and
> anywhere from 5 to 2000 intervals. We expect a query to take less tha
On 2017-06-05 19:00 (-0700), "Roger Fischer (CW)" wrote:
> Hello,
>
> is there any intent to support "order by" and "limit" on aggregated values?
>
> For time series data, top n queries are quite common. Group-by was the first
> step towards supporting such queries, but ordering by value and
sync
>> queries and token-aware load balancing to partition the query and execute
>> it in parallel on each node.
>>
>>
>>
>> Thanks…
>>
>>
>>
>> Roger
>>
>>
>>
>>
>>
>> *From:* DuyHai Doan [mailto:doanduy.
e.
>
>
>
> Thanks…
>
>
>
> Roger
>
>
>
>
>
> *From:* DuyHai Doan [mailto:doanduy...@gmail.com]
> *Sent:* Tuesday, June 06, 2017 12:31 AM
> *To:* Roger Fischer (CW)
> *Cc:* user@cassandra.apache.org
> *Subject:* Re: Order by for aggregated values
parallel on each node.
Thanks…
Roger
From: DuyHai Doan [mailto:doanduy...@gmail.com]
Sent: Tuesday, June 06, 2017 12:31 AM
To: Roger Fischer (CW)
Cc: user@cassandra.apache.org
Subject: Re: Order by for aggregated values
First Group By is only allowed on partition keys and clustering columns, not
support “order by” on aggregated values.
Thanks…
Roger
From: DuyHai Doan [mailto:doanduy...@gmail.com]
Sent: Tuesday, June 06, 2017 12:31 AM
To: Roger Fischer (CW)
Cc: user@cassandra.apache.org
Subject: Re: Order by for aggregated values
First Group By is only allowed on partition keys and
First Group By is only allowed on partition keys and clustering columns,
not on arbitrary column. The internal implementation of group by tries to
fetch data on clustering order to avoid having to "re-sort" them in memory
which would be very expensive
Second, group by works best when restricted to
