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https://issues.apache.org/jira/browse/HBASE-6874?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13491700#comment-13491700
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Karthik Ranganathan commented on HBASE-6874:
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Matt - Yes, we had chatted about that as well. But right now, the focus is to
improve scan performance from memory. We should definitely cycle back to that
as well. The thought is if we can get one thread reading one block from memory
to outperform the disk, we can get the parallelism from multiple on-going
scans. In addition, the scan perf when I started this effort was around 20MB/s
from memory, so no matter how much we read from the disk, it would be slow.
Now, I am able to benchmark more than 100MB/s (all results on one thread), so
other things make sense. Will publish my results in detail.
> 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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