the default values for these two param are:
https://github.com/KylinOLAP/Kylin/blob/124121764a3eb0652032c8add97f02708aa5fd3a/common/src/main/java/org/apache/kylin/common/KylinConfig.java#L445

On Wed, Jun 17, 2015 at 10:08 AM, hongbin ma <[email protected]> wrote:

> hi Luca,
>
> Kylin selectively caches queries those
> 1. take a lot of time to execute, or
> 2. scanned a lot of HBase rows
> The logic is in
> https://github.com/KylinOLAP/Kylin/blob/0.7.1/server/src/main/java/org/apache/kylin/rest/controller/QueryController.java#L209
>
> In other words, Kylin only caches slow queries. Caching all the query
> results regardless of its cost  is not worth the effort. You can adjust
> these two parameters kylin.query.cache.threshold.duration
> and kylin.query.cache.threshold.scancount in kylin.properties to change its
> behavior
>
>
> On Tue, Jun 16, 2015 at 7:16 PM, Luca Costabello <
> [email protected]> wrote:
>
>> Hello all,
>>
>> I am running the 0.7.1-incubating, installed from the release binary.
>>
>> Currently, repeated executions of certain queries result in cache hits (as
>> I expected)
>> Example:
>> If I execute twice this query, I get results served from cache the second
>> time ("hitCache": true):
>>
>> SELECT column_1, column_2
>> FROM FACT_TABLE
>> INNER JOIN DIMENSION_TABLE on FACT_TABLE.id = DIMENSION_TABLE.id
>> WHERE date_ < date'2014-08-31'
>> GROUP BY column_1, column_2
>>
>> On the other hand, repeated execution of the query below never lead to
>> cache hits (i.e. I always end up with "hitCache": false).
>>
>> SELECT count(*) as total_count
>> FROM FACT_TABLE
>> WHERE date_ < date'2014-08-31'
>>
>> My use case would highly benefit from extensive caching, since I have few
>> heavy repeated queries to issue to the system.
>> I am not familiar with current Kylin cache strategy, and I was wondering
>> if
>> someone could give me some hints.
>> Besides, I have not found any cache-related parameter in property files,
>> aside from kylin.query.cache.enabled in conf/kylin.properties
>> (kylin.query.cache.enabled is set to true in my case)
>>
>> Thanks
>>
>> luca
>>
>
>
>
> --
> 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

Reply via email to