[jira] [Updated] (OAK-5042) Improve caching of segments

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

     [ https://issues.apache.org/jira/browse/OAK-5042?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Michael Dürig updated OAK-5042:
-------------------------------
    Attachment: OAK-5042.png

> Improve caching of segments
> ---------------------------
>
>                 Key: OAK-5042
>                 URL: https://issues.apache.org/jira/browse/OAK-5042
>             Project: Jackrabbit Oak
>          Issue Type: Improvement
>          Components: segment-tar
>            Reporter: Michael Dürig
>            Assignee: Michael Dürig
>              Labels: performance
>             Fix For: 1.5.13
>
>         Attachments: OAK-5042.png
>
>
> Various aspects of how Segment Tar caches segments could possibly improved. The current cache is a result of replacing the former ad-hoc cache with a proper one in OAK-3055. While the former was prone to contention under concurrent load the current cache is too oblivious about reads: read accesses are always served through {{SegmentId.segment}} and never actually hit the cache. This results in frequently accessed segments not to be seen as such by the cache and potentially being prematurely evicted. 
> Possibly approaches to address this problem include: 
> * Reinstantiating the cache we had pre OAK-3055 but making in fully concurrent. 
> * Convey the information about read accesses to the current cache. 
> * In either of the above cases avoid bulk segments from being placed into the cache. 



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)