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https://issues.apache.org/jira/browse/HBASE-12031?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14144021#comment-14144021
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Vladimir Rodionov commented on HBASE-12031:
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[~lhofhansl
{quote}
in your tests - out of curiosity - what happens when you force compaction into
always using preads?
{quote}
I have not tried that as since implementation still use streaming reads when
possible, but if we disable streaming reads and will use preads with read
ahead, we will see some performance degradation, of course. Streaming reads are
still more efficient than preads with read aheads.
> Parallel Scanners inside Region
> -------------------------------
>
> Key: HBASE-12031
> URL: https://issues.apache.org/jira/browse/HBASE-12031
> Project: HBase
> Issue Type: New Feature
> Components: Performance, Scanners
> Affects Versions: 0.98.6
> Reporter: Vladimir Rodionov
> Assignee: Vladimir Rodionov
> Fix For: 1.0.0, 2.0.0, 0.98.7, 0.99.1
>
> Attachments: HBASE-12031.2.patch, HBASE-12031.patch,
> ParallelScannerDesign.pdf, hbase-12031-tests.tar.gz
>
>
> This JIRA to improve performance of multiple scanners running on a same
> region in parallel. The scenarios where we will get the performance benefits:
> * New TableInputFormat with input splits smaller than HBase Region.
> * Scanning during compaction (Compaction scanner and application scanner over
> the same Region).
> Some JIRAs related to this one:
> https://issues.apache.org/jira/browse/HBASE-7336
> https://issues.apache.org/jira/browse/HBASE-5979
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