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https://issues.apache.org/jira/browse/HBASE-25972?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17847621#comment-17847621
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Hudson commented on HBASE-25972:
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Results for branch branch-2.6
[build #120 on
builds.a.o|https://ci-hbase.apache.org/job/HBase%20Nightly/job/branch-2.6/120/]:
(/) *{color:green}+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-2.6/120/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-2.6/120/JDK8_20Nightly_20Build_20Report_20_28Hadoop2_29/]
(/) {color:green}+1 jdk8 hadoop3 checks{color}
-- For more information [see jdk8 (hadoop3)
report|https://ci-hbase.apache.org/job/HBase%20Nightly/job/branch-2.6/120/JDK8_20Nightly_20Build_20Report_20_28Hadoop3_29/]
(/) {color:green}+1 jdk11 hadoop3 checks{color}
-- For more information [see jdk11
report|https://ci-hbase.apache.org/job/HBase%20Nightly/job/branch-2.6/120/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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