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https://issues.apache.org/jira/browse/HBASE-6874?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13490940#comment-13490940
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Matt Corgan commented on HBASE-6874:
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Have you guys considered the possibility fetching multiple blocks in a single
call to HDFS? If compressed block size is 10KB, then maybe large scans should
be requesting 100+ blocks (1MB) at a time given that rotational drives can read
several MB in the same time they can do a seek. The prefetch thread could chop
the 1MB result into the individual blocks before putting them into the block
cache.
> Implement prefetching for scanners
> ----------------------------------
>
> Key: HBASE-6874
> URL: https://issues.apache.org/jira/browse/HBASE-6874
> Project: HBase
> Issue Type: Sub-task
> Reporter: Karthik Ranganathan
> Assignee: Karthik Ranganathan
>
> I did some quick experiments by scanning data that should be completely in
> memory and found that adding pre-fetching increases the throughput by about
> 50% from 26MB/s to 39MB/s.
> The idea is to perform the next in a background thread, and keep the result
> ready. When the scanner's next comes in, return the pre-computed result and
> issue another background read.
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