Re: Materialized Views and TTLs

2018-02-23 Thread Valentina Crisan
Hello Akash,

Depends what you mean by downsampling: for example if you have time as
clustering key in your table you can order data DESC inside partitions and
then just do a select with per partition limit ( last 10 entries in each
partition for example).
But if you would like to extract a totally random subset of data from an
existing table (which would correspond more to downsampling) - then you
need to do this in an analytical layer on top of Cassandra ( like Apache
Spark). As far as I know you cannot do this in Cassandra.

Valentina

On Fri, Feb 23, 2018 at 9:44 PM, Akash Gangil  wrote:

> Hi Valentina,
>
> In that case, are there any well defined ways on how to do downsampling of
> data in C*?
>
> thanks!
>
>
> On Fri, Feb 23, 2018 at 11:36 AM, Valentina Crisan <
> valentina.cri...@gmail.com> wrote:
>
>> Hello,
>>
>> as far as I know it is not intended for MV's to have a different TTL than
>> the base tables. There was patch released at some point to not allow TTL
>> setting on MV (https://issues.apache.org/jira/browse/CASSANDRA-12868).
>> MV's should inherit the TTL of the base table.
>>
>> Valentina
>>
>> On Fri, Feb 23, 2018 at 6:42 PM, Akash Gangil 
>> wrote:
>>
>>> Hi,
>>>
>>> I had a couple of questions:
>>>
>>> 1. Can I create a materialized view on a table with a TTL longer than
>>> the base table? For ex: my materialized view TTL is 1 month while my base
>>> table TTL is 1 week.
>>>
>>> 2. In the above scenario, since the data in my base table would be gone
>>> after a week, would it impact data in the materialized view?
>>>
>>> My use case if I have some time series data, which is stored in the base
>>> table by_minute and I want to downsample it to by_month. So my base table
>>> stores by_minute data but my materialized view stores stores by_week data.
>>>
>>> thanks!
>>>
>>> --
>>> Akash
>>>
>>
>>
>
>
> --
> Akash
>


Re: Materialized Views and TTLs

2018-02-23 Thread Akash Gangil
Hi Valentina,

In that case, are there any well defined ways on how to do downsampling of
data in C*?

thanks!


On Fri, Feb 23, 2018 at 11:36 AM, Valentina Crisan <
valentina.cri...@gmail.com> wrote:

> Hello,
>
> as far as I know it is not intended for MV's to have a different TTL than
> the base tables. There was patch released at some point to not allow TTL
> setting on MV (https://issues.apache.org/jira/browse/CASSANDRA-12868).
> MV's should inherit the TTL of the base table.
>
> Valentina
>
> On Fri, Feb 23, 2018 at 6:42 PM, Akash Gangil 
> wrote:
>
>> Hi,
>>
>> I had a couple of questions:
>>
>> 1. Can I create a materialized view on a table with a TTL longer than the
>> base table? For ex: my materialized view TTL is 1 month while my base table
>> TTL is 1 week.
>>
>> 2. In the above scenario, since the data in my base table would be gone
>> after a week, would it impact data in the materialized view?
>>
>> My use case if I have some time series data, which is stored in the base
>> table by_minute and I want to downsample it to by_month. So my base table
>> stores by_minute data but my materialized view stores stores by_week data.
>>
>> thanks!
>>
>> --
>> Akash
>>
>
>


-- 
Akash


Re: Materialized Views and TTLs

2018-02-23 Thread Valentina Crisan
Hello,

as far as I know it is not intended for MV's to have a different TTL than
the base tables. There was patch released at some point to not allow TTL
setting on MV (https://issues.apache.org/jira/browse/CASSANDRA-12868). MV's
should inherit the TTL of the base table.

Valentina

On Fri, Feb 23, 2018 at 6:42 PM, Akash Gangil  wrote:

> Hi,
>
> I had a couple of questions:
>
> 1. Can I create a materialized view on a table with a TTL longer than the
> base table? For ex: my materialized view TTL is 1 month while my base table
> TTL is 1 week.
>
> 2. In the above scenario, since the data in my base table would be gone
> after a week, would it impact data in the materialized view?
>
> My use case if I have some time series data, which is stored in the base
> table by_minute and I want to downsample it to by_month. So my base table
> stores by_minute data but my materialized view stores stores by_week data.
>
> thanks!
>
> --
> Akash
>


Materialized Views and TTLs

2018-02-23 Thread Akash Gangil
Hi,

I had a couple of questions:

1. Can I create a materialized view on a table with a TTL longer than the
base table? For ex: my materialized view TTL is 1 month while my base table
TTL is 1 week.

2. In the above scenario, since the data in my base table would be gone
after a week, would it impact data in the materialized view?

My use case if I have some time series data, which is stored in the base
table by_minute and I want to downsample it to by_month. So my base table
stores by_minute data but my materialized view stores stores by_week data.

thanks!

-- 
Akash