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https://issues.apache.org/jira/browse/HBASE-25972?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17847492#comment-17847492
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Hudson commented on HBASE-25972:
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Results for branch branch-2
        [build #1057 on 
builds.a.o|https://ci-hbase.apache.org/job/HBase%20Nightly/job/branch-2/1057/]: 
(x) *{color:red}-1 overall{color}*
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details (if available):

(/) {color:green}+1 general checks{color}
-- For more information [see general 
report|https://ci-hbase.apache.org/job/HBase%20Nightly/job/branch-2/1057/General_20Nightly_20Build_20Report/]


(/) {color:green}+1 jdk8 hadoop2 checks{color}
-- For more information [see jdk8 (hadoop2) 
report|https://ci-hbase.apache.org/job/HBase%20Nightly/job/branch-2/1057/JDK8_20Nightly_20Build_20Report_20_28Hadoop2_29/]


(x) {color:red}-1 jdk8 hadoop3 checks{color}
-- For more information [see jdk8 (hadoop3) 
report|https://ci-hbase.apache.org/job/HBase%20Nightly/job/branch-2/1057/JDK8_20Nightly_20Build_20Report_20_28Hadoop3_29/]


(/) {color:green}+1 jdk11 hadoop3 checks{color}
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report|https://ci-hbase.apache.org/job/HBase%20Nightly/job/branch-2/1057/JDK11_20Nightly_20Build_20Report_20_28Hadoop3_29/]


(/) {color:green}+1 source release artifact{color}
-- See build output for details.


(/) {color:green}+1 client integration test{color}


> Dual File Compaction
> --------------------
>
>                 Key: HBASE-25972
>                 URL: https://issues.apache.org/jira/browse/HBASE-25972
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Kadir Ozdemir
>            Assignee: Kadir Ozdemir
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 2.7.0, 3.0.0-beta-2, 2.6.1, 2.5.9
>
>
> HBase stores tables row by row in its files, HFiles. An HFile is composed of 
> blocks. The number of rows stored in a block depends on the row sizes. The 
> number of rows per block gets lower when rows get larger on disk due to 
> multiple row versions since HBase stores all row versions sequentially in the 
> same HFile after compaction. However, applications (e.g., Phoenix) mostly 
> query the most recent row versions.
> The default compactor in HBase compacts HFiles into one file. This Jira 
> introduces a new store file writer which writes the retained cells by 
> compaction into two files, which will be called DualFileWriter. One of these 
> files will include the live cells. This file will be called a live-version 
> file. The other file will include the rest of the cells, that is, historical 
> versions. This file will be called a historical-version file. DualFileWriter 
> will work with the default compactor.
> The historical files will not be read for the scans scanning latest row 
> versions. This eliminates scanning unnecessary cell versions in compacted 
> files and thus it is expected to improve performance of these scans.



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