however it still requires caution if you're using a timestamp column.
Timestamp column may has very high cardinality if you don't apply any
normalization on it. Usually it's suggested to truncate the second or
minute to reduce cardinality.
On Tue, Dec 15, 2015 at 4:07 PM, hongbin ma <mahong...@apache.org> wrote:
> in 2.x versions, timestamp is being supported
>
> On Tue, Dec 15, 2015 at 4:00 PM, yu feng <olaptes...@gmail.com> wrote:
>
>> Hi All :
>> I build a cube, fact table like this :
>> hive> describe testtimestamp;
>> OK
>> ts timestamp
>> fname string
>> lname string
>> type int
>> cost int
>>
>> I build a cube with dimensions 'ts', 'fname', 'lname' and type, However,
>> after build the cube , I run query like 'select dictinct ts from
>> testtimestamp', and It return :
>> +---------------------+
>> | TS |
>> +---------------------+
>> | 2015-12-14 16:00:00 |
>> | 2015-12-12 16:00:00 |
>> | 2015-12-11 16:00:00 |
>> | 2015-12-09 16:00:00 |
>> | 2015-12-10 16:00:00 |
>> | 2015-12-15 16:00:00 |
>> | 2015-12-13 16:00:00 |
>> +---------------------+
>>
>> then, this is a error result, I query it in hive , it return :
>> 2015-12-10 00:00:00
>> 2015-12-11 01:02:03
>> 2015-12-12 05:02:10
>> 2015-12-12 06:08:10
>> 2015-12-12 16:02:18
>> 2015-12-13 06:28:40
>> 2015-12-14 03:20:15
>> 2015-12-14 11:04:18
>> 2015-12-15 10:13:21
>> 2015-12-16 12:04:12
>>
>> I know the reason is kylin use DateStrDictionary to build dictionary for
>> column type like ("date")、("time")、("datetime")、("timestamp"); then it
>> will
>> try to use SimpleDateFormat("yyyy-MM-dd") parsing column values, so after
>> build dictionary, timestamp value in same day transform to the same value
>> of Date.
>>
>> Is it a bug or some other consideration ?
>>
>
>
>
> --
> Regards,
>
> *Bin Mahone | 马洪宾*
> Apache Kylin: http://kylin.io
> Github: https://github.com/binmahone
>
--
Regards,
*Bin Mahone | 马洪宾*
Apache Kylin: http://kylin.io
Github: https://github.com/binmahone
