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https://issues.apache.org/jira/browse/HBASE-9272?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13749319#comment-13749319
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Lars Hofhansl commented on HBASE-9272:
--------------------------------------
You might notice that 30m * 10 * 108 = 30gb is actually impossible to pipe over
a 1ge link in 187s.
Turns out I had only scanned one of the column families in my test code. So the
numbers are for selecting only 5 of columns.
Even then we're approaching what can be streamed of a 1ge link. 80mb/s out of
the max 125mb/s.
In the case where everything is filtered we're churning through 15gb in the
cache in less then 2s in 100 byte chunks. Not too bad.
> A simple parallel, unordered scanner
> ------------------------------------
>
> Key: HBASE-9272
> URL: https://issues.apache.org/jira/browse/HBASE-9272
> Project: HBase
> Issue Type: New Feature
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Priority: Minor
> Attachments: ParallelClientScanner.java, ParallelClientScanner.java
>
>
> The contract of ClientScanner is to return rows in sort order. That limits
> the order in which region can be scanned.
> I propose a simple ParallelScanner that does not have this requirement and
> queries regions in parallel, return whatever gets returned first.
> This is generally useful for scans that filter a lot of data on the server,
> or in cases where the client can very quickly react to the returned data.
> I have a simple prototype (doesn't do error handling right, and might be a
> bit heavy on the synchronization side - it used a BlockingQueue to hand data
> between the client using the scanner and the threads doing the scanning, it
> also could potentially starve some scanners long enugh to time out at the
> server).
> On the plus side, it's only a 130 lines of code. :)
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