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Posted to issues@kylin.apache.org by "ASF subversion and git services (JIRA)" <ji...@apache.org> on 2018/10/29 11:28:05 UTC

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

    [ https://issues.apache.org/jira/browse/KYLIN-2894?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16667043#comment-16667043 ] 

ASF subversion and git services commented on KYLIN-2894:
--------------------------------------------------------

Commit 7e1cdeda85dc293efe8bd408444d7bbef8401be6 in kylin's branch refs/heads/master from Ma,Gang
[ https://gitbox.apache.org/repos/asf?p=kylin.git;h=7e1cded ]

KYLIN-2894 add a new signature calculator FactTableRealizationSetCalculator


> 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
>            Reporter: Zhong Yanghong
>            Assignee: Wang Ken
>            Priority: Major
>
> 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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