Thanks for the heads-up! As I am running Kylin in sandbox mode (kylin.sandbox=true), I also had to increase the size of ehcache cache: by default all "maxBytesLocalHeap" values were set to 1M in ehcache-test.xml (which is ehcache config file used in sandbox mode), so queries that led to bigger payloads always skipped the cache.
Cheers, luca On Wed, Jun 17, 2015 at 3:09 AM, hongbin ma <[email protected]> wrote: > 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 >
