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https://issues.apache.org/jira/browse/HBASE-17339?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15782330#comment-15782330
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Edward Bortnikov commented on HBASE-17339:
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[~davelatham], [~yangzhe1991] - thanks for pointing out the historical context.
Indeed, the idea will not work in peer clusters with concurrent updates.
However, it seems that there are enough interesting use cases that deserve
treatment.
This optimization is complementary to in-memory flush & compaction (see
HBASE-14918). The latter brings its own value, but in conjunction the two
produce very impressive reduction in read latency. [~eshcar], maybe you could
attach some perf results? Thanks.
> Scan-Memory-First Optimization for Get Operation
> ------------------------------------------------
>
> Key: HBASE-17339
> URL: https://issues.apache.org/jira/browse/HBASE-17339
> Project: HBase
> Issue Type: Improvement
> Reporter: Eshcar Hillel
> Attachments: HBASE-17339-V01.patch
>
>
> The current implementation of a get operation (to retrieve values for a
> specific key) scans through all relevant stores of the region; for each store
> both memory components (memstores segments) and disk components (hfiles) are
> scanned in parallel.
> We suggest to apply an optimization that speculatively scans memory-only
> components first and only if the result is incomplete scans both memory and
> disk.
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