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https://issues.apache.org/jira/browse/HBASE-8420?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13655030#comment-13655030
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Jimmy Xiang commented on HBASE-8420:
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The configurable max prefetched result size is set to 512 M by default.
Whenever a scanner is called to fetch data, we will check if the caller thread
is a prefetcher thread based on the thread name. If it is a prefetcher thread,
the result wire size is added to global atomic long variable (a counter).
After the prefetched result is retrieved, the same amount is reduced from the
counter. If the counter value is over the pre-configured threshold, the next
prefetching will not be scheduled. This is a rough control. We don't do micro
control, i.e. stop a prefetcher thread in the middle.
> Port HBASE-6874 Implement prefetching for scanners from 0.89-fb
> -----------------------------------------------------------------
>
> Key: HBASE-8420
> URL: https://issues.apache.org/jira/browse/HBASE-8420
> Project: HBase
> Issue Type: Improvement
> Reporter: Jimmy Xiang
> Assignee: Jimmy Xiang
> Attachments: 0.94-8420_v1.patch, 0.94-8420_v2.patch,
> trunk-8420_v1.patch, trunk-8420_v2.patch, trunk-8420_v3.patch
>
>
> This should help scanner performance. We should have it in trunk.
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