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Date: Mon, 18 Feb 2013 01:16:12 +0000 (UTC)
From: "Lars Hofhansl (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
Message-ID: <JIRA.12632745.1361097345161.300114.1361150171997@arcas>
In-Reply-To: <JIRA.12632745.1361097345161@arcas>
References: <JIRA.12632745.1361097345161@arcas>
Subject: [jira] [Commented] (HBASE-7868) HFile performance regression
 between 0.92 and 0.94
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    [ https://issues.apache.org/jira/browse/HBASE-7868?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13580355#comment-13580355 ] 

Lars Hofhansl commented on HBASE-7868:
--------------------------------------

Did the same scan test with cacheBlocks disabled for the scan. All data is in the OS cache (no actual disk reads). With that I can not discern any changes between commenting the schemaMetrics stuff, vs not.

[~jmspaggi] What are you plotting? Time or number of ops? I assume it's time, since all of my perf improvements went into 0.94.4.

                
> HFile performance regression between 0.92 and 0.94
> --------------------------------------------------
>
>                 Key: HBASE-7868
>                 URL: https://issues.apache.org/jira/browse/HBASE-7868
>             Project: HBase
>          Issue Type: Bug
>          Components: io
>    Affects Versions: 0.94.5
>            Reporter: Matteo Bertozzi
>            Assignee: Matteo Bertozzi
>             Fix For: 0.94.6
>
>         Attachments: FilteredScan.png, hfileperf-graphs.png
>
>
> By HFilePerformanceEvaluation seems that 0.94 is slower then 0.92
> Looking at the profiler for the Scan path, seems that most of the time, compared to 92, is spent in the metrics dictionary lookup. [~eclark] pointed out the new per family/block metrics.
> By commenting the metrics call in HFileReaderV2, the performance seems to get better, but maybe metrics is not the only problem.

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