[jira] [Commented] (HBASE-26083) L1 miss metric is incorrect when using CombinedBlockCache

["Yutong Xiao (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-26083?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17381085#comment-17381085 ] 

Yutong Xiao commented on HBASE-26083:
-------------------------------------

[~anoop.hbase] I have updated the github MR #3474 any comment? If not, I would update the branch-2 & master next.

> L1 miss metric is incorrect when using CombinedBlockCache
> ---------------------------------------------------------
>
>                 Key: HBASE-26083
>                 URL: https://issues.apache.org/jira/browse/HBASE-26083
>             Project: HBase
>          Issue Type: Bug
>          Components: BlockCache
>            Reporter: Yutong Xiao
>            Assignee: Yutong Xiao
>            Priority: Major
>
> In CombinedBlockCache getBlock method
> {code:java}
> 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 l2Cache.getBlock.
>     // We are not in a position to exactly look at LRU cache or BC as BlockType may not be getting
>     // passed always.
>     return l1Cache.containsBlock(cacheKey)?
>         l1Cache.getBlock(cacheKey, caching, repeat, updateCacheMetrics):
>         l2Cache.getBlock(cacheKey, caching, repeat, updateCacheMetrics);
>   }
> {code}
> If L1 does not contains cacheKey, it will never check it in L1, so that L1 miss metrics is always 0.



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