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From "stack (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-15240) Go Big BucketCache Fixes
Date Fri, 12 Feb 2016 20:41:18 GMT

    [ https://issues.apache.org/jira/browse/HBASE-15240?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15145260#comment-15145260
] 

stack commented on HBASE-15240:
-------------------------------

Doing quick profile on prefetch -- it takes a long time to load the block cache -- I see the
attached when we are prefetching one big file. We are mostly in readBlockDataInternal, which
is no surprise. Then there is the usual suspects, compares. For context, perf top shows readBlockDataInternal
doing < 1% of total CPU so pepper the JMC 25% with that knowledge. Looking at inlining,
I see:

org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderImpl::readBlockData (354 bytes)   too
big

readBlockDataInternal is likely the same but inlining reports it being zombified.. so maybe
we should make it final but if I were to guess, inlining would again report it too big.

I thought I was seeing parse of path Strings but must have been imagining it... Need to make
prefetch go faster.

(Matteo and I were looking at something else last night slightly related.... readBlock in
blockSeek from HFileReaderImpl... it was taking 10%+ of CPU when YCSB doing mostly writes.
It was reported as too big to inline too. Need to fix. And then there are all the compares
both here and what we were looking at last night. We need to work on those -- avoid some (e.g.
Matteo asked why we are doing family parse and compares when below a Store at all?) -- and
study/profile/fix up the reset. Just saying.)



> Go Big BucketCache Fixes
> ------------------------
>
>                 Key: HBASE-15240
>                 URL: https://issues.apache.org/jira/browse/HBASE-15240
>             Project: HBase
>          Issue Type: Umbrella
>          Components: BucketCache
>            Reporter: stack
>            Assignee: stack
>         Attachments: Screen Shot 2016-02-10 at 6.27.26 AM.png
>
>
> Umbrella issue to which we will attach issues that prevent bucketcache going big; there's
a few.



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