[jira] [Commented] (HBASE-18002) Investigate why bucket cache filling up in file mode in an exisitng file is slower

["Anoop Sam John (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-18002?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15998666#comment-15998666 ] 

Anoop Sam John commented on HBASE-18002:
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File mode BC and so persistence = true. So when the RS starts and the preload, there are entries already in the BC (backingMap) right?  What % of the total size is already occupied this way?  Impact of eviction process?   How things would have been if isPersistent() was false from FileIOEngine also?

> Investigate why bucket cache filling up in file mode in an exisitng file  is slower
> -----------------------------------------------------------------------------------
>
>                 Key: HBASE-18002
>                 URL: https://issues.apache.org/jira/browse/HBASE-18002
>             Project: HBase
>          Issue Type: Sub-task
>          Components: BucketCache
>    Affects Versions: 2.0.0
>            Reporter: ramkrishna.s.vasudevan
>             Fix For: 2.0.0
>
>
> This issue was observed when we recently did some tests with SSD based bucket cache. Similar thing was also reported by @stack and [~danielpol] while doing some of these bucket cache related testing.
> When we try to preload a bucket cache (in file mode) with a new file the bucket cache fills up quite faster and there not much 'failedBlockAdditions'. But when the same bucket cache is filled up with a preexisitng file ( that had already some entries filled up) this time it has more 'failedBlockAdditions' and the cache does not fill up faster. Investigate why this happens. 



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