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From "Nick Dimiduk (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-11520) Simplify offheap cache config by removing the confusing "hbase.bucketcache.percentage.in.combinedcache"
Date Thu, 17 Jul 2014 15:57:05 GMT

    [ https://issues.apache.org/jira/browse/HBASE-11520?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14065050#comment-14065050
] 

Nick Dimiduk commented on HBASE-11520:
--------------------------------------

bq. Given this latter, the package-info as it is in the patch is right by my reckoning. From
LruBlockCache

Oh. I thought the only place BucketCache was entering the picture was via CombinedBlockCache:

{noformat}
  public Cacheable getBlock(BlockCacheKey cacheKey, boolean caching,
      boolean repeat, boolean updateCacheMetrics) {
    // TODO: is there a hole here, or just awkwardness since in the lruCache getBlock
    // we end up calling bucketCache.getBlock.
    if (lruCache.containsBlock(cacheKey)) {
      return lruCache.getBlock(cacheKey, caching, repeat, updateCacheMetrics);
    }
    return bucketCache.getBlock(cacheKey, caching, repeat, updateCacheMetrics);
  }
{noformat}

I didn't grock your meaning of LruBlockCache reaching into it's victimHandler at read time.
So really, setting hbase.bucketcache.combinedcache.enabled=false means "cache data blocks
in Lru first" while =true means "data blocks never go to lru, only bucket".

> Simplify offheap cache config by removing the confusing "hbase.bucketcache.percentage.in.combinedcache"
> -------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-11520
>                 URL: https://issues.apache.org/jira/browse/HBASE-11520
>             Project: HBase
>          Issue Type: Sub-task
>          Components: io
>    Affects Versions: 0.99.0
>            Reporter: stack
>            Assignee: stack
>             Fix For: 0.99.0, 2.0.0
>
>         Attachments: 11520.txt, 11520v2.txt, 11520v3.txt, 11520v3.txt
>
>
> Remove "hbase.bucketcache.percentage.in.combinedcache".  It is unnecessary complication
of block cache config.  Let L1 config setup be as it is whether a L2 present or not, just
set hfile.block.cache.size (not hbase.bucketcache.size * (1.0 - hbase.bucketcache.percentage.in.combinedcache)).
 For L2, let hbase.bucketcache.size be the actual size of the bucket cache, not hbase.bucketcache.size
* hbase.bucketcache.percentage.in.combinedcache.
> Attached patch removes the config. and updates docs.  Adds tests to confirm configs are
as expected whether a CombinedBlockCache deploy or a strict L1+L2 deploy.



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