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https://issues.apache.org/jira/browse/HBASE-29039?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Eungsop Yoo updated HBASE-29039:
--------------------------------
Status: Patch Available (was: Open)
> Optimize read performance for accumulated delete markers on the same row or
> cell
> --------------------------------------------------------------------------------
>
> Key: HBASE-29039
> URL: https://issues.apache.org/jira/browse/HBASE-29039
> Project: HBase
> Issue Type: Improvement
> Affects Versions: 2.5.10, 2.6.1
> Reporter: Eungsop Yoo
> Priority: Major
>
> As delete markers are accumulated on the same row or cell, Get opertions slow
> down. It can be reproduced by follow HBase shell commands.
> {code}
> create 'test', 'c'
> java_import org.apache.hadoop.hbase.client.Delete
> java_import org.apache.hadoop.hbase.TableName
> java_import java.lang.System
> con = @hbase.instance_variable_get(:@connection)
> table = con.getTable(TableName.valueOf('test'))
> 1000.times do |i|
> # batch 10000 deletes with different timestamps every 10 seconds
> now = System.currentTimeMillis()
> dels = 10000.times.map do |i|
> del = Delete.new(Bytes.toBytes('row'))
> del.addFamily(Bytes.toBytes('c'), now + i)
> end
> table.delete(dels)
> sleep(10)
> puts "i - #{i}"
> get 'test', 'row'
> end
> {code}
> {code}
> i - 0
> COLUMN
> CELL
> 0 row(s)
> Took 0.0251 seconds
> ...
> i - 10
> COLUMN
> CELL
> 0 row(s)
> Took 0.0412 seconds
> ...
> i - 20
> COLUMN
> CELL
> 0 row(s)
> Took 0.0760 seconds
> ...
> i - 30
> COLUMN
> CELL
> 0 row(s)
> Took 0.1014 seconds
> ...
> i - 40
> COLUMN
> CELL
> 0 row(s)
> Took 0.1616 seconds
> ...
> {code}
> But the performance of Get operations can be optimized by using SEEK_NEXT_COL.
> {code}
> i - 1
> COLUMN
> CELL
> 0 row(s)
> Took 0.0087 seconds
> ...
> i - 11
> COLUMN
> CELL
> 0 row(s)
> Took 0.0077 seconds
> ...
> i - 21
> COLUMN
> CELL
> 0 row(s)
> Took 0.0087 seconds
> ...
> {code}
> Please review the PR.
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