[jira] [Commented] (KYLIN-2894) Change the query cache expiration strategy by signature checking

["liyang (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KYLIN-2894?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16195961#comment-16195961 ] 

liyang commented on KYLIN-2894:
-------------------------------

The key is how the signature is computed. Could you explain more on the design?

Another (perhaps more straightforward) design is invalidate by project. Have you thought of that?

> Change the query cache expiration strategy by signature checking
> ----------------------------------------------------------------
>
>                 Key: KYLIN-2894
>                 URL: https://issues.apache.org/jira/browse/KYLIN-2894
>             Project: Kylin
>          Issue Type: Sub-task
>          Components: Query Engine
>    Affects Versions: v2.1.0
>            Reporter: Zhong Yanghong
>            Assignee: Zhong Yanghong
>             Fix For: v2.2.0
>
>
> Currently to invalid query cache, {{CacheService}} will either invoke {{cleanDataCache}} or {{cleanAllDataCache}}. Both methods will clear all of the query cache, which is very inefficient. In eBay PROD environment, there's around 400 cubing jobs per day, which means the query cache will be cleared very 4 minutes. Then we introduced a signature based cache invalidation strategy. The basic idea is as follows:
> * Add a signature for {{SQLResponse}}, here we choose the cube last build time
> * When fetch {{SQLResponse}} for cache, first check whether the signature is consistent. If not, this cached value is overdue and will be invalidate.



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