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https://issues.apache.org/jira/browse/HBASE-4434?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13113160#comment-13113160
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jirapos...@reviews.apache.org commented on HBASE-4434:
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/2034/
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Review request for Michael Stack, Jonathan Gray and Mikhail Bautin.
Summary
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The increase in blocks read in one sub-test case is due to HBASE-4466, which
should be fixed soon. It is primarily an accounting issue, not an extra cache
miss.
This addresses bug HBASE-4434.
https://issues.apache.org/jira/browse/HBASE-4434
Diffs
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http://svn.apache.org/repos/asf/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/StoreFileScanner.java
1174514
http://svn.apache.org/repos/asf/hbase/trunk/src/test/java/org/apache/hadoop/hbase/regionserver/TestBlocksRead.java
1174514
Diff: https://reviews.apache.org/r/2034/diff
Testing
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Ran TestBlocksRead. Will run the entire suite as well. On our 89 based internal
branch, the tests passed without any issues.
Thanks,
Kannan
> Don't do HFile Scanner next() unless the next KV is needed:
> -----------------------------------------------------------
>
> Key: HBASE-4434
> URL: https://issues.apache.org/jira/browse/HBASE-4434
> Project: HBase
> Issue Type: Improvement
> Reporter: Kannan Muthukkaruppan
> Assignee: Kannan Muthukkaruppan
>
> When a seek/reseek is done on StoreFileScanner, in addition to setting the
> current KV, it also does a HFileScanner level next() ahead of time even if
> the next KV is never actually required. This inefficiency can potentially
> result in additional disk seeks and sub-optimal use of the block cache
> (primarily for cases where the KVs are large and each occupies an HFile block
> of its own).
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